1
|
Heimeier D, Garland EC, Eichenberger F, Garrigue C, Vella A, Baker CS, Carroll EL. A pan-cetacean MHC amplicon sequencing panel developed and evaluated in combination with genome assemblies. Mol Ecol Resour 2024; 24:e13955. [PMID: 38520161 DOI: 10.1111/1755-0998.13955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 12/01/2023] [Accepted: 12/22/2023] [Indexed: 03/25/2024]
Abstract
The major histocompatibility complex (MHC) is a highly polymorphic gene family that is crucial in immunity, and its diversity can be effectively used as a fitness marker for populations. Despite this, MHC remains poorly characterised in non-model species (e.g., cetaceans: whales, dolphins and porpoises) as high gene copy number variation, especially in the fast-evolving class I region, makes analyses of genomic sequences difficult. To date, only small sections of class I and IIa genes have been used to assess functional diversity in cetacean populations. Here, we undertook a systematic characterisation of the MHC class I and IIa regions in available cetacean genomes. We extracted full-length gene sequences to design pan-cetacean primers that amplified the complete exon 2 from MHC class I and IIa genes in one combined sequencing panel. We validated this panel in 19 cetacean species and described 354 alleles for both classes. Furthermore, we identified likely assembly artefacts for many MHC class I assemblies based on the presence of class I genes in the amplicon data compared to missing genes from genomes. Finally, we investigated MHC diversity using the panel in 25 humpback and 30 southern right whales, including four paternity trios for humpback whales. This revealed copy-number variable class I haplotypes in humpback whales, which is likely a common phenomenon across cetaceans. These MHC alleles will form the basis for a cetacean branch of the Immuno-Polymorphism Database (IPD-MHC), a curated resource intended to aid in the systematic compilation of MHC alleles across several species, to support conservation initiatives.
Collapse
Affiliation(s)
- Dorothea Heimeier
- School of Biological Sciences, University of Auckland-Waipapa Taumata Rau, Auckland, New Zealand
| | - Ellen C Garland
- Sea Mammal Research Unit, School of Biology, University of St. Andrews, Fife, UK
| | - Franca Eichenberger
- Sea Mammal Research Unit, School of Biology, University of St. Andrews, Fife, UK
| | - Claire Garrigue
- UMR ENTROPIE, (IRD, Université de La Réunion, Université de la Nouvelle-Calédonie, IFREMER, CNRS, Laboratoire d'Excellence-CORAIL), Nouméa, New Caledonia
- Opération Cétacés, Nouméa, New Caledonia
| | - Adriana Vella
- Conservation Biology Research Group, Department of Biology, University of Malta, Msida, Malta
| | - C Scott Baker
- Marine Mammal Institute, Hatfield Marine Science Center, Oregon State University, Corvallis, Oregon, USA
| | - Emma L Carroll
- School of Biological Sciences, University of Auckland-Waipapa Taumata Rau, Auckland, New Zealand
| |
Collapse
|
2
|
Jackson TK, Rhode C. Comparative genomics of dusky kob (Argyrosomus japonicus, Sciaenidae) conspecifics: Evidence for speciation and the genetic mechanisms underlying traits. JOURNAL OF FISH BIOLOGY 2024. [PMID: 38885946 DOI: 10.1111/jfb.15844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 04/17/2024] [Accepted: 05/28/2024] [Indexed: 06/20/2024]
Abstract
Dusky kob (Argyrosomus japonicus) is a commercially important finfish, indigenous to South Africa, Australia, and China. Previous studies highlighted differences in genetic composition, life history, and morphology of the species across geographic regions. A draft genome sequence of 0.742 Gb (N50 = 5.49 Mb; BUSCO completeness = 97.8%) and 22,438 predicted protein-coding genes was generated for the South African (SA) conspecific. A comparison with the Chinese (CN) conspecific revealed a core set of 32,068 orthologous protein clusters across both genomes. The SA genome exhibited 440 unique clusters compared to 1928 unique clusters in the CN genome. Transportation and immune response processes were overrepresented among the SA accessory genome, whereas the CN accessory genome was enriched for immune response, DNA transposition, and sensory detection (FDR-adjusted p < 0.01). These unique clusters may represent an adaptive component of the species' pangenome that could explain population divergence due to differential environmental specialisation. Furthermore, 700 single-copy orthologues (SCOs) displayed evidence of positive selection between the SA and CN genomes, and globally these genomes shared only 92% similarity, suggesting they might be distinct species. These genes primarily play roles in metabolism and digestion, illustrating the evolutionary pathways that differentiate the species. Understanding these genomic mechanisms underlying adaptation and evolution within and between species provides valuable insights into growth and maturation of kob, traits that are particularly relevant to commercial aquaculture.
Collapse
Affiliation(s)
- Tassin Kim Jackson
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
| | - Clint Rhode
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
| |
Collapse
|
3
|
Li S, Li S, Liu S, Lu S, Li J, Cheng S, Zhang S, Huang S, Li J, Jian F. Portulaca oleracea exhibited anti-coccidian activity, fortified the gut microbiota of Hu lambs. AMB Express 2024; 14:50. [PMID: 38700828 PMCID: PMC11068709 DOI: 10.1186/s13568-024-01705-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2023] [Accepted: 04/13/2024] [Indexed: 05/06/2024] Open
Abstract
Coccidia of the genus Eimeria are important pathogens that cause coccidiosis in livestock and poultry. Due to the expansion of intensive farming, coccidiosis has become more difficult to control. In addition, the continued use of anti-coccidiosis drugs has led to drug resistance and residue. Some herbs used in traditional Chinese medicine (TCM) have been shown to alleviate the clinical symptoms of coccidiosis, while enhancing immunity and growth performance (GP) of livestock and poultry. Previous in vitro and in vivo studies have reported that the TCM herb Portulaca oleracea exhibited anti-parasitic activities. In total, 36 female Hu lambs were equally divided into six treatment groups: PL (low-dose P. oleracea), PH (high-dose P. oleracea), PW (P. oleracea water extract), PE (P. oleracea ethanol extract), DIC (diclazuril), and CON (control). The treatment period was 14 days. The McMaster counting method was used to evaluate the anti-coccidiosis effects of the different treatments. Untargeted metabolomics and 16S rRNA gene sequencing were used to investigate the effects of treatment on the gut microbiota (GM) and GP. The results showed that P. oleracea ameliorated coccidiosis, improved GP, increased the abundances of beneficial bacteria, and maintained the composition of the GM, but failed to completely clear coccidian oocysts. The Firmicutes to Bacteroides ratio was significantly increased in the PH group. P. oleracea increased metabolism of tryptophan as well as some vitamins and cofactors in the GM and decreased the relative content of arginine, tryptophan, niacin, and other nutrients, thereby promoting intestinal health and enhancing GP. As an alternative to the anti-coccidiosis drug DIC, P. oleracea effectively inhibited growth of coccidia, maintained the composition of the GM, promoted intestinal health, and increased nutrient digestibility.
Collapse
Affiliation(s)
- Shiheng Li
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China
| | - Senyang Li
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China
- International Joint Research Laboratory for Zoonotic Diseases of Henan, Zhengzhou, 450046, Henan, China
| | - Shuaiqi Liu
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China
| | - Shunli Lu
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China
| | - Jing Li
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China
| | - Shuqi Cheng
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China
| | - Sumei Zhang
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China
| | - Shucheng Huang
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China
| | - Junqiang Li
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China
| | - Fuchun Jian
- College of Animal Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, Henan, China.
- Key Laboratory of Quality and Safety Control of Poultry Products, Ministry of Agriculture and Rural Affairs, Zhengzhou, Henan, People's Republic of China.
| |
Collapse
|
4
|
Efstratiou A, Gaigher A, Künzel S, Teles A, Lenz TL. Template-specific optimization of NGS genotyping pipelines reveals allele-specific variation in MHC gene expression. Mol Ecol Resour 2024; 24:e13935. [PMID: 38332480 DOI: 10.1111/1755-0998.13935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 01/19/2024] [Accepted: 01/25/2024] [Indexed: 02/10/2024]
Abstract
Using high-throughput sequencing for precise genotyping of multi-locus gene families, such as the major histocompatibility complex (MHC), remains challenging, due to the complexity of the data and difficulties in distinguishing genuine from erroneous variants. Several dedicated genotyping pipelines for data from high-throughput sequencing, such as next-generation sequencing (NGS), have been developed to tackle the ensuing risk of artificially inflated diversity. Here, we thoroughly assess three such multi-locus genotyping pipelines for NGS data, the DOC method, AmpliSAS and ACACIA, using MHC class IIβ data sets of three-spined stickleback gDNA, cDNA and "artificial" plasmid samples with known allelic diversity. We show that genotyping of gDNA and plasmid samples at optimal pipeline parameters was highly accurate and reproducible across methods. However, for cDNA data, the gDNA-optimal parameter configuration yielded decreased overall genotyping precision and consistency between pipelines. Further adjustments of key clustering parameters were required tο account for higher error rates and larger variation in sequencing depth per allele, highlighting the importance of template-specific pipeline optimization for reliable genotyping of multi-locus gene families. Through accurate paired gDNA-cDNA typing and MHC-II haplotype inference, we show that MHC-II allele-specific expression levels correlate negatively with allele number across haplotypes. Lastly, sibship-assisted cDNA-typing of MHC-I revealed novel variants linked in haplotype blocks, and a higher-than-previously-reported individual MHC-I allelic diversity. In conclusion, we provide novel genotyping protocols for the three-spined stickleback MHC-I and -II genes, and evaluate the performance of popular NGS-genotyping pipelines. We also show that fine-tuned genotyping of paired gDNA-cDNA samples facilitates amplification bias-corrected MHC allele expression analysis.
Collapse
Affiliation(s)
- Artemis Efstratiou
- Research Unit for Evolutionary Immunogenomics, Department of Biology, University of Hamburg, Hamburg, Germany
- Research Group for Evolutionary Immunogenomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Arnaud Gaigher
- Research Unit for Evolutionary Immunogenomics, Department of Biology, University of Hamburg, Hamburg, Germany
- Research Group for Evolutionary Immunogenomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
- CIBIO-InBIO, Research Center in Biodiversity and Genetic Resources, University of Porto, Vairão, Portugal
| | - Sven Künzel
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Ana Teles
- Research Unit for Evolutionary Immunogenomics, Department of Biology, University of Hamburg, Hamburg, Germany
- Research Group for Evolutionary Immunogenomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
- Department of Evolutionary Ecology, Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Tobias L Lenz
- Research Unit for Evolutionary Immunogenomics, Department of Biology, University of Hamburg, Hamburg, Germany
- Research Group for Evolutionary Immunogenomics, Max Planck Institute for Evolutionary Biology, Plön, Germany
| |
Collapse
|
5
|
Roved J. MHCtools 1.5: Analysis of MHC Sequencing Data in R. Methods Mol Biol 2024; 2809:275-295. [PMID: 38907904 DOI: 10.1007/978-1-0716-3874-3_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2024]
Abstract
The genes of the major histocompatibility complex (MHC) play a vital role in the vertebrate immune system and have attracted considerable interest in evolutionary biology. While the MHC has been characterized in detail in humans (human leukocyte antigen, HLA) and in model organisms such as the mouse, studies in non-model organisms often lack prior knowledge about structure, genetic variability, and evolutionary properties of this locus. MHC genotyping in non-model species commonly relies on PCR-based amplicon sequencing, and while several published protocols facilitate generation of MHC sequence data, there is a lack of transparent and standardized tools for downstream data analysis.Here, I present the R package MHCtools version 1.5, which contains 15 tools that (i) assist accurate MHC genotyping from high-throughput amplicon sequencing data, and provide standardized methods to analyze (ii) MHC diversity, (iii) MHC supertypes, and (iv) MHC haplotypes.I hope that MHCtools will be helpful in future studies of the MHC in non-model species and that it may help to advance our understanding of the important roles of the MHC in ecology and evolution.
Collapse
Affiliation(s)
- Jacob Roved
- Section for Molecular Ecology and Evolution, GLOBE Institute, University of Copenhagen, Copenhagen, Denmark.
| |
Collapse
|
6
|
Sebastian A, Migalska M, Gaczorek T. AmpliSAS and AmpliHLA: Web Server and Local Tools for MHC Typing of Non-model Species and Human Using NGS Data. Methods Mol Biol 2024; 2809:37-66. [PMID: 38907889 DOI: 10.1007/978-1-0716-3874-3_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/24/2024]
Abstract
AmpliSAS and AmpliHLA are tools for automatic genotyping of MHC genes from high-throughput sequencing data. AmpliSAS is designed specifically to analyze amplicon sequencing data from non-model species and it is able to perform de novo genotyping without any previous knowledge of the reference alleles. AmpliHLA is a human specific version; it performs HLA typing by comparing sequenced variants against human reference alleles from the IMGT/HLA database. Both tools are available in AmpliSAT web-server as well as scripts for local/server installation. Here we describe the installation and deployment of AmpliSAS and AmpliHLA Perl scripts and dependencies on a local or a server computer. We will show how to run them in the command line using as examples four genotyping protocols: the first two use amplicon sequencing data to genotype the MHC genes of a passerine bird and human respectively; the third and fourth present the HLA typing of a human cell line starting from RNA and exome sequencing data respectively.
Collapse
Affiliation(s)
| | - Magdalena Migalska
- Genomics and Experimental Evolution Group, Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Krakow, Poland.
| | - Tomasz Gaczorek
- Genomics and Experimental Evolution Group, Institute of Environmental Sciences, Faculty of Biology, Jagiellonian University, Krakow, Poland
| |
Collapse
|
7
|
Hardigan MA, Feldmann MJ, Carling J, Zhu A, Kilian A, Famula RA, Cole GS, Knapp SJ. A medium-density genotyping platform for cultivated strawberry using DArTag technology. THE PLANT GENOME 2023; 16:e20399. [PMID: 37940627 DOI: 10.1002/tpg2.20399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/22/2023] [Indexed: 11/10/2023]
Abstract
Genomic prediction in breeding populations containing hundreds to thousands of parents and seedlings is prohibitively expensive with current high-density genetic marker platforms designed for strawberry. We developed mid-density panels of molecular inversion probes (MIPs) to be deployed with the "DArTag" marker platform to provide a low-cost, high-throughput genotyping solution for strawberry genomic prediction. In total, 7742 target single nucleotide polymorphism (SNP) regions were used to generate MIP assays that were tested with a screening panel of 376 octoploid Fragaria accessions. We evaluated the performance of DArTag assays based on genotype segregation, amplicon coverage, and their ability to produce subgenome-specific amplicon alignments to the FaRR1 assembly and subsequent alignment-based variant calls with strong concordance to DArT's alignment-free, count-based genotype reports. We used a combination of marker performance metrics and physical distribution in the FaRR1 assembly to select 3K and 5K production panels for genotyping of large strawberry populations. We show that the 3K and 5K DArTag panels are able to target and amplify homologous alleles within subgenomic sequences with low-amplification bias between reference and alternate alleles, supporting accurate genotype calling while producing marker genotypes that can be treated as functionally diploid for quantitative genetic analysis. The 3K and 5K target SNPs show high levels of polymorphism in diverse F. × ananassa germplasm and UC Davis cultivars, with mean pairwise diversity (π) estimates of 0.40 and 0.32 and mean heterozygous genotype frequencies of 0.35 and 0.33, respectively.
Collapse
Affiliation(s)
- Michael A Hardigan
- USDA-ARS, Horticultural Crops Production and Genetic Improvement Research Unit, Corvallis, Oregon, USA
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - Mitchell J Feldmann
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - Jason Carling
- Diversity Arrays Technology, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Anyu Zhu
- Diversity Arrays Technology, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Andrzej Kilian
- Diversity Arrays Technology, University of Canberra, Bruce, Australian Capital Territory, Australia
| | - Randi A Famula
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - Glenn S Cole
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| | - Steven J Knapp
- Department of Plant Sciences, University of California Davis, Davis, California, USA
| |
Collapse
|
8
|
Extensive MHC class IIβ diversity across multiple loci in the small-spotted catshark (Scyliorhinus canicula). Sci Rep 2023; 13:3837. [PMID: 36882519 PMCID: PMC9992475 DOI: 10.1038/s41598-023-30876-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/02/2023] [Indexed: 03/09/2023] Open
Abstract
The major histocompatibility complex (MHC) is a multigene family responsible for pathogen detection, and initiation of adaptive immune responses. Duplication, natural selection, recombination, and their resulting high functional genetic diversity spread across several duplicated loci are the main hallmarks of the MHC. Although these features were described in several jawed vertebrate lineages, a detailed MHC IIβ characterization at the population level is still lacking for chondrichthyans (chimaeras, rays and sharks), i.e. the most basal lineage to possess an MHC-based adaptive immune system. We used the small-spotted catshark (Scyliorhinus canicula, Carcharhiniformes) as a case-study species to characterize MHC IIβ diversity using complementary molecular tools, including publicly available genome and transcriptome datasets, and a newly developed high-throughput Illumina sequencing protocol. We identified three MHC IIβ loci within the same genomic region, all of which are expressed in different tissues. Genetic screening of the exon 2 in 41 individuals of S. canicula from a single population revealed high levels of sequence diversity, evidence for positive selection, and footprints of recombination. Moreover, the results also suggest the presence of copy number variation in MHC IIβ genes. Thus, the small-spotted catshark exhibits characteristics of functional MHC IIβ genes typically observed in other jawed vertebrates.
Collapse
|
9
|
Fu M, Eimes JA, Waldman B. Divergent allele advantage in the MHC and amphibian emerging infectious disease. INFECTION, GENETICS AND EVOLUTION 2023; 111:105429. [PMID: 36990307 DOI: 10.1016/j.meegid.2023.105429] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 02/20/2023] [Accepted: 03/22/2023] [Indexed: 03/29/2023]
Abstract
Genetic variation in the major histocompatibility complex (MHC) may be associated with resistance to the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd). The pathogen originated in Asia, then spread worldwide, causing amphibian population declines and species extinctions. We compared the expressed MHC IIβ1 alleles of a Bd-resistant toad species, Bufo gargarizans, from South Korea with those of a Bd-susceptible Australasian frog species, Litoria caerulea. We found at least six expressed MHC IIβ1 loci in each of the two species. Amino acid diversity encoded by these MHC alleles was similar between species, but the genetic divergence of those alleles known for broader pathogen-derived peptide binding was greater in the Bd-resistant species. In addition, we found a potentially rare allele in one resistant individual from the Bd-susceptible species. Deep next-generation sequencing recovered approximately triple the genetic resolution accessible from traditional cloning-based genotyping. Targeting more than one MHC IIβ1 expressed locus enables us to better understand how host MHC may adapt to emerging infectious diseases.
Collapse
|
10
|
Nicolas-Espinosa J, Carvajal M. Genome-wide identification and biological relevance of broccoli aquaporins. THE PLANT GENOME 2022; 15:e20262. [PMID: 36263901 DOI: 10.1002/tpg2.20262] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 08/10/2022] [Indexed: 06/16/2023]
Abstract
Broccoli (Brassica oleracea var. italica) is an important crop worldwide, and its regular consumption is associated with health benefits due to the presence of various bioactive compounds. An optimal water balance and homeostasis are needed for plant growth; in this sense, aquaporins play a crucial role. As a result of a genome-wide search, a total of 65 aquaporin genes were identified in broccoli. The aquaporins were classified according to their phylogenetic relationships with other Brassicas species and Arabidopsis thaliana, and evolutionary events of gene duplication were also assessed, highlighting the tendency of NIPs (Nodulin-26-like Intrinsic Proteins) to duplicate. Also, the chromosomal localization, gene duplication, the study of the conserved motifs, and the tertiary structure were determined in broccoli. Functional predictive analyses were also carried out, which, together with the expression analyses in different broccoli plant tissues, allowed the prediction of the biological role of each aquaporin isoform. BoiPIP1-2a and BoiPIP1-2b showed higher expression in all the plant tissues when compared with other aquaporins. BoiTIP1-2b also showed high expression levels and was associated with nitrogen compounds transport such as urea. However, NIPs, through their differential expression and the tandem duplications of the isoforms, were revealed as the putative main actors in the response of broccoli plants to abiotic stress responses. The results of this work pointed to the physiological significance of each aquaporin isoform of broccoli, opening a new field of knowledge and constituting the first step of further in vivo analyses.
Collapse
Affiliation(s)
- Juan Nicolas-Espinosa
- Aquaporins Group, Plant Nutrition Dep., Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Campus Univ. de Espinardo, Edificio 25, Murcia, 30100, Spain
| | - Micaela Carvajal
- Aquaporins Group, Plant Nutrition Dep., Centro de Edafología y Biología Aplicada del Segura (CEBAS-CSIC), Campus Univ. de Espinardo, Edificio 25, Murcia, 30100, Spain
| |
Collapse
|
11
|
Evaluation of Genetic Diversity and Parasite-Mediated Selection of MHC Class I Genes in Emberiza godlewskii (Passeriformes: Emberizidae). DIVERSITY 2022. [DOI: 10.3390/d14110925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The major histocompatibility complex (MHC) is a multi-copy immune gene family in vertebrates. Its genes are highly variable and code for antigen-presenting molecules. Characterization of MHC genes in different species and investigating the mechanisms that shape MHC diversity is an important goal in understanding the evolution of biological diversity. Here we developed a next-generation sequencing (NGS) protocol to genotype the MHC class I genes of 326 Godlewski’s buntings (Emberiza godlewskii) sampled in the Western mountain area of Beijing from 2014 to 2016. A total of 184 functional alleles were identified, including both non-classical and classical alleles, clustering into nine supertypes. Compared with other passerine birds, the number of MHC class I alleles per individual in Godlewski’s buntings is high (mean 16.1 ± 3.3, median 16). In addition, we demonstrated signatures of historical and contemporary selection on MHC genes. Reflecting historical selection, ten amino acid sites in the antigen-binding domain showed signatures of balancing selection, eight of which exhibit high amino acid polymorphism. In terms of contemporary selection, we found that specific MHC supertypes were nominally associated with the infection of two malaria parasite lineages. These findings indicate the action of historical and possibly also contemporary balancing selection and suggest negative frequency-dependent or fluctuating selection as possible selection mechanisms.
Collapse
|
12
|
Intronic primers reveal unexpectedly high major histocompatibility complex diversity in Antarctic fur seals. Sci Rep 2022; 12:17933. [PMID: 36289307 PMCID: PMC9606363 DOI: 10.1038/s41598-022-21658-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/29/2022] [Indexed: 01/20/2023] Open
Abstract
The major histocompatibility complex (MHC) is a group of genes comprising one of the most important components of the vertebrate immune system. Consequently, there has been much interest in characterising MHC variation and its relationship with fitness in a variety of species. Due to the exceptional polymorphism of MHC genes, careful PCR primer design is crucial for capturing all of the allelic variation present in a given species. We therefore developed intronic primers to amplify the full-length 267 bp protein-coding sequence of the MHC class II DQB exon 2 in the Antarctic fur seal. We then characterised patterns of MHC variation among mother-offspring pairs from two breeding colonies and detected 19 alleles among 771 clone sequences from 56 individuals. The distribution of alleles within and among individuals was consistent with a single-copy, classical DQB locus showing Mendelian inheritance. Amino acid similarity at the MHC was significantly associated with genome-wide relatedness, but no relationship was found between MHC heterozygosity and genome-wide heterozygosity. Finally, allelic diversity was several times higher than reported by a previous study based on partial exon sequences. This difference appears to be related to allele-specific amplification bias, implying that primer design can strongly impact the inference of MHC diversity.
Collapse
|
13
|
Performance Comparison of Different Approaches in Genotyping MHC-DRB: The Contrast between Single-Locus and Multi-Locus Species. Animals (Basel) 2022; 12:ani12182452. [PMID: 36139311 PMCID: PMC9495155 DOI: 10.3390/ani12182452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/12/2022] [Accepted: 09/13/2022] [Indexed: 11/17/2022] Open
Abstract
Major histocompatibility complex (MHC) genes are widely recognised as valuable markers for wildlife genetic studies given their extreme polymorphism and functional importance in fitness-related traits. Newly developed genotyping methods, which rely on the use of next-generation sequencing (NGS), are gradually replacing traditional cloning and Sanger sequencing methods in MHC genotyping studies. Allele calling in NGS methods remains challenging due to extreme polymorphism and locus multiplication in the MHC coupled with allele amplification bias and the generation of artificial sequences. In this study, we compared the performance of molecular cloning with Illumina and Ion Torrent NGS sequencing in MHC-DRB genotyping of single-locus species (roe deer) and species with multiple DRB loci (red deer) in an attempt to adopt a reliable and straightforward method that does not require complex bioinformatic analyses. Our results show that all methods work similarly well in roe deer, but we demonstrate non-consistency in results across methods in red deer. With Illumina sequencing, we detected a maximum number of alleles in 10 red deer individuals (42), while other methods were somewhat less accurate as they scored 69–81% of alleles detected with Illumina sequencing.
Collapse
|
14
|
Cortazar-Chinarro M, Meurling S, Schroyens L, Siljestam M, Richter-Boix A, Laurila A, Höglund J. Major Histocompatibility Complex Variation and Haplotype Associated Survival in Response to Experimental Infection of Two Bd-GPL Strains Along a Latitudinal Gradient. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.915271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
While both innate and adaptive immune system mechanisms have been implicated in resistance against the chytrid fungus Batrachochytrium dendrobatidis (Bd), studies on the role of specific MHC haplotypes on Bd infection are rare. Here, we studied variation in MHC Class IIB loci in the common toad Bufo bufo along a latitudinal gradient across Sweden. In general, Swedish toad populations had few MHC Class IIB haplotypes and MHC diversity declined from south (13 haplotypes) to the north (four haplotypes). The low diversity may compromise the ability of northern populations to fight emerging disease, such as Bd. In a laboratory experiment, we infected newly metamorphosed toads with two strains of the Global Pandemic Lineage of the fungus (Bd-GPL) and compared survival with sham controls. Bd-infected toads had lower survival compared to controls. Moreover, survival was dependent on the Bd-strain and northern toads had lower Bd-mediated survival than southern individuals. MHC diversity was lower in northern toads. All northern experimental animals were monomorphic for a single MHC haplotype, whereas we found seven different haplotypes in southern experimental animals. In southern toads, survival was dependent on both Bd-strain and MHC haplotype suggesting differential infection dynamics depending on both Bd-strain and host immune system characteristics.
Collapse
|
15
|
Wong ATC, Lam DK, Poon ESK, Chan DTC, Sin SYW. Intra-specific copy number variation of MHC class II genes in the Siamese fighting fish. Immunogenetics 2022; 74:327-346. [PMID: 35229174 DOI: 10.1007/s00251-022-01255-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 02/04/2022] [Indexed: 11/28/2022]
Abstract
Duplicates of genes for major histocompatibility complex (MHC) molecules can be subjected to selection independently and vary markedly in their evolutionary rates, sequence polymorphism, and functional roles. Therefore, without a thorough understanding of their copy number variation (CNV) in the genome, the MHC-dependent fitness consequences within a species could be misinterpreted. Studying the intra-specific CNV of this highly polymorphic gene, however, has long been hindered by the difficulties in assigning alleles to loci and the lack of high-quality genomic data. Here, using the high-quality genome of the Siamese fighting fish (Betta splendens), a model for mate choice studies, and the whole-genome sequencing (WGS) data of 17 Betta species, we achieved locus-specific amplification of their three classical MHC class II genes - DAB1, DAB2, and DAB3. By performing quantitative PCR and depth-of-coverage analysis using the WGS data, we revealed intra-specific CNV at the DAB3 locus. We identified individuals that had two allelic copies (i.e., heterozygous or homozygous) or one allele (i.e., hemizygous) and individuals without this gene. The CNV was due to the deletion of a 20-kb-long genomic region harboring both the DAA3 and DAB3 genes. We further showed that the three DAB genes were under different modes of selection, which also applies to their corresponding DAA genes that share similar pattern of polymorphism. Our study demonstrates a combined approach to study CNV within a species, which is crucial for the understanding of multigene family evolution and the fitness consequences of CNV.
Collapse
Affiliation(s)
- Anson Tsz Chun Wong
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong SAR, China
| | - Derek Kong Lam
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong SAR, China
| | - Emily Shui Kei Poon
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong SAR, China
| | - David Tsz Chung Chan
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong SAR, China
| | - Simon Yung Wa Sin
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Road, Hong Kong SAR, China.
| |
Collapse
|
16
|
Roved J, Hansson B, Stervander M, Hasselquist D, Westerdahl H. MHCtools - an R package for MHC high-throughput sequencing data: genotyping, haplotype and supertype inference, and downstream genetic analyses in non-model organisms. Mol Ecol Resour 2022; 22:2775-2792. [PMID: 35587892 PMCID: PMC9543685 DOI: 10.1111/1755-0998.13645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/11/2022] [Accepted: 05/11/2022] [Indexed: 11/30/2022]
Abstract
The major histocompatibility complex (MHC) plays a central role in the vertebrate adaptive immune system and has been of long-term interest in evolutionary biology. While several protocols have been developed for MHC genotyping, there is a lack of transparent and standardized tools for downstream analysis of MHC data. Here, we present the R package MHCtools and demonstrate the use of its functions to (i) assist accurate MHC genotyping from high-throughput amplicon-sequencing data, (ii) infer functional MHC supertypes using bootstrapped clustering analysis, (iii) identify segregating MHC haplotypes from family data, and (iv) analyse functional and genetic distances between MHC sequences. We employed MHCtools to analyse MHC class I (MHC-I) amplicon data of 559 great reed warblers (Acrocephalus arundinaceus). We identified 390 MHC-I alleles which clustered into 14 functional supertypes. A phylogenetic analysis and analyses of positive selection suggested that the MHC-I alleles belonged to several distinct functional groups. We furthermore identified 107 segregating haplotypes among 116 families, and found substantial variation in diversity with 4-21 MHC-I alleles and 3-13 MHC-I supertypes per haplotype. Finally, we show that the great reed warbler haplotypes harboured combinations of MHC-I supertypes with greater functional divergence than observed in simulated populations of possible haplotypes, a result that is in accordance with the divergent allele advantage hypothesis. Our study demonstrates the power of MHCtools to support genotyping and analysis of MHC in non-model species, which we hope will encourage broad implementation among researchers in MHC genetics and evolution.
Collapse
Affiliation(s)
- Jacob Roved
- GLOBE Institute, Section for Evolutionary Genomics, University of Copenhagen, 1350, Copenhagen K, Denmark
| | - Bengt Hansson
- Department of Biology, Molecular Ecology and Evolution Lab, Lund University, Ecology Building, 223 62, Lund, Sweden
| | - Martin Stervander
- Department of Biology, Molecular Ecology and Evolution Lab, Lund University, Ecology Building, 223 62, Lund, Sweden.,Department of Biology and Environmental Science, Faculty of Health and Life Sciences, Linnaeus University, 391 82, Kalmar, Sweden.,Bird Group, Department of Life Sciences, Natural History Museum, Akeman Street, Hertfordshire, HP23 6AP, UK
| | - Dennis Hasselquist
- Department of Biology, Molecular Ecology and Evolution Lab, Lund University, Ecology Building, 223 62, Lund, Sweden.,Bird Group, Department of Life Sciences, Natural History Museum, Akeman Street, Hertfordshire, HP23 6AP, UK
| | - Helena Westerdahl
- Department of Biology, Molecular Ecology and Evolution Lab, Lund University, Ecology Building, 223 62, Lund, Sweden
| |
Collapse
|
17
|
Gillingham MAF, Montero BK, Wihelm K, Grudzus K, Sommer S, Santos PSC. A novel workflow to improve genotyping of multigene families in wildlife species: An experimental set-up with a known model system. Mol Ecol Resour 2020; 21:982-998. [PMID: 33113273 DOI: 10.1111/1755-0998.13290] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 10/19/2020] [Accepted: 10/22/2020] [Indexed: 12/30/2022]
Abstract
Genotyping complex multigene families in novel systems is particularly challenging. Target primers frequently amplify simultaneously multiple loci leading to high PCR and sequencing artefacts such as chimeras and allele amplification bias. Most genotyping pipelines have been validated in nonmodel systems whereby the real genotype is unknown and the generation of artefacts may be highly repeatable. Further hindering accurate genotyping, the relationship between artefacts and genotype complexity (i.e. number of alleles per genotype) within a PCR remains poorly described. Here, we investigated the latter by experimentally combining multiple known major histocompatibility complex (MHC) haplotypes of a model organism (chicken, Gallus gallus, 43 artificial genotypes with 2-13 alleles per amplicon). In addition to well-defined 'optimal' primers, we simulated a nonmodel species situation by designing 'cross-species' primers based on sequence data from closely related Galliform species. We applied a novel open-source genotyping pipeline (ACACIA; https://gitlab.com/psc_santos/ACACIA), and compared its performance with another, previously published pipeline (AmpliSAS). Allele calling accuracy was higher when using ACACIA (98.5% versus 97% and 77.8% versus 75% for the 'optimal' and 'cross-species' data sets, respectively). Systematic allele dropout of three alleles owing to primer mismatch in the 'cross-species' data set explained high allele calling repeatability (100% when using ACACIA) despite low accuracy, demonstrating that repeatability can be misleading when evaluating genotyping workflows. Genotype complexity was positively associated with nonchimeric artefacts, chimeric artefacts (nonlinearly by levelling when amplifying more than 4-6 alleles) and allele amplification bias. Our study exemplifies and demonstrates pitfalls researchers should avoid to reliably genotype complex multigene families.
Collapse
Affiliation(s)
- Mark A F Gillingham
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm Universität, Ulm, Germany
| | - B Karina Montero
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm Universität, Ulm, Germany.,Zoological Institute, Animal Ecology and Conservation, Biocenter Grindel, Universität Hamburg, Hamburg,, Germany
| | - Kerstin Wihelm
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm Universität, Ulm, Germany
| | - Kara Grudzus
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm Universität, Ulm, Germany
| | - Simone Sommer
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm Universität, Ulm, Germany
| | - Pablo S C Santos
- Institute of Evolutionary Ecology and Conservation Genomics, Ulm Universität, Ulm, Germany
| |
Collapse
|
18
|
MHC Genotyping by SSCP and Amplicon-Based NGS Approach in Chamois. Animals (Basel) 2020; 10:ani10091694. [PMID: 32962183 PMCID: PMC7552744 DOI: 10.3390/ani10091694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 09/13/2020] [Accepted: 09/16/2020] [Indexed: 11/17/2022] Open
Abstract
Genes of the major histocompatibility complex (MHC) code for cell surface proteins essential for adaptive immunity. They show the most outstanding genetic diversity in vertebrates, which has been connected with various fitness traits and thus with the long-term persistence of populations. In this study, polymorphism of the MHC class II DRB locus was investigated in chamois with Single-Strand Conformation Polymorphism (SSCP)/Sanger genotyping and Ion Torrent S5 next-generation sequencing (NGS). From eight identified DRB variants in 28 individuals, five had already been described, and three were new, undescribed alleles. With conventional SSCP/Sanger sequencing, we were able to detect seven alleles, all of which were also detected with NGS. We found inconsistencies in the individual genotypes between the two methods, which were mainly caused by allelic dropout in the SSCP/Sanger method. Six out of 28 individuals were falsely classified as homozygous with SSCP/Sanger analysis. Overall, 25% of the individuals were identified as genotyping discrepancies between the two methods. Our results show that NGS technologies are better performing in sequencing highly variable regions such as the MHC, and they also have a higher detection capacity, thus allowing a more accurate description of the genetic composition, which is crucial for evolutionary and population genetic studies.
Collapse
|
19
|
Tripathi P, Singh J, Lal JA, Tripathi V. Next-Generation Sequencing: An Emerging Tool for Drug Designing. Curr Pharm Des 2020; 25:3350-3357. [PMID: 31544713 DOI: 10.2174/1381612825666190911155508] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 09/05/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND With the outbreak of high throughput next-generation sequencing (NGS), the biological research of drug discovery has been directed towards the oncology and infectious disease therapeutic areas, with extensive use in biopharmaceutical development and vaccine production. METHOD In this review, an effort was made to address the basic background of NGS technologies, potential applications of NGS in drug designing. Our purpose is also to provide a brief introduction of various Nextgeneration sequencing techniques. DISCUSSIONS The high-throughput methods execute Large-scale Unbiased Sequencing (LUS) which comprises of Massively Parallel Sequencing (MPS) or NGS technologies. The Next geneinvolved necessarily executes Largescale Unbiased Sequencing (LUS) which comprises of MPS or NGS technologies. These are related terms that describe a DNA sequencing technology which has revolutionized genomic research. Using NGS, an entire human genome can be sequenced within a single day. CONCLUSION Analysis of NGS data unravels important clues in the quest for the treatment of various lifethreatening diseases and other related scientific problems related to human welfare.
Collapse
Affiliation(s)
- Pooja Tripathi
- Department of Computational Biology and Bioinformatics, Jacob Institute of Biotechnology and Bioengineering, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj, India
| | - Jyotsna Singh
- Department of Molecular and Cellular Engineering, Jacob Institute of Biotechnology and Bioengineering, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj, India
| | - Jonathan A Lal
- Department of Molecular and Cellular Engineering, Jacob Institute of Biotechnology and Bioengineering, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj, India.,Institute for Public Health Genomics, Maastricht University, Maastricht, Netherlands
| | - Vijay Tripathi
- Department of Molecular and Cellular Engineering, Jacob Institute of Biotechnology and Bioengineering, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj, India
| |
Collapse
|
20
|
Cortázar-Chinarro M, Meyer-Lucht Y, Van der Valk T, Richter-Boix A, Laurila A, Höglund J. Antimicrobial peptide and sequence variation along a latitudinal gradient in two anurans. BMC Genet 2020; 21:38. [PMID: 32228443 PMCID: PMC7106915 DOI: 10.1186/s12863-020-00839-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 03/06/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND While there is evidence of both purifying and balancing selection in immune defense genes, large-scale genetic diversity in antimicrobial peptides (AMPs), an important part of the innate immune system released from dermal glands in the skin, has remained uninvestigated. Here we describe genetic diversity at three AMP loci (Temporin, Brevinin and Palustrin) in two ranid frogs (Rana arvalis and R. temporaria) along a 2000 km latitudinal gradient. We amplified and sequenced part of the Acidic Propiece domain and the hypervariable Mature Peptide domain (~ 150-200 bp) in the three genes using Illumina Miseq and expected to find decreased AMP genetic variation towards the northern distribution limit of the species similarly to studies on MHC genetic patterns. RESULTS We found multiple loci for each AMP and relatively high gene diversity, but no clear pattern of geographic genetic structure along the latitudinal gradient. We found evidence of trans-specific polymorphism in the two species, indicating a common evolutionary origin of the alleles. Temporin and Brevinin did not form monophyletic clades suggesting that they belong to the same gene family. By implementing codon evolution models we found evidence of strong positive selection acting on the Mature Peptide. We also found evidence of diversifying selection as indicated by divergent allele frequencies among populations and high Theta k values. CONCLUSION Our results suggest that AMPs are an important source of adaptive diversity, minimizing the chance of microorganisms developing resistance to individual peptides.
Collapse
Affiliation(s)
- Maria Cortázar-Chinarro
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden.
| | - Yvonne Meyer-Lucht
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden.,Centre for Paleogenetics Svante Arrhenius väg 20C, SE-106 91, Stockholm, Sweden
| | - Tom Van der Valk
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden
| | - Alex Richter-Boix
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden
| | - Anssi Laurila
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden
| | - Jacob Höglund
- Animal Ecology/Department of Ecology and Genetics, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden
| |
Collapse
|
21
|
Lindsay WR, Andersson S, Bererhi B, Höglund J, Johnsen A, Kvarnemo C, Leder EH, Lifjeld JT, Ninnes CE, Olsson M, Parker GA, Pizzari T, Qvarnström A, Safran RJ, Svensson O, Edwards SV. Endless forms of sexual selection. PeerJ 2019; 7:e7988. [PMID: 31720113 PMCID: PMC6839514 DOI: 10.7717/peerj.7988] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 10/04/2019] [Indexed: 12/11/2022] Open
Abstract
In recent years, the field of sexual selection has exploded, with advances in theoretical and empirical research complementing each other in exciting ways. This perspective piece is the product of a "stock-taking" workshop on sexual selection and sexual conflict. Our aim is to identify and deliberate on outstanding questions and to stimulate discussion rather than provide a comprehensive overview of the entire field. These questions are organized into four thematic sections we deem essential to the field. First we focus on the evolution of mate choice and mating systems. Variation in mate quality can generate both competition and choice in the opposite sex, with implications for the evolution of mating systems. Limitations on mate choice may dictate the importance of direct vs. indirect benefits in mating decisions and consequently, mating systems, especially with regard to polyandry. Second, we focus on how sender and receiver mechanisms shape signal design. Mediation of honest signal content likely depends on integration of temporally variable social and physiological costs that are challenging to measure. We view the neuroethology of sensory and cognitive receiver biases as the main key to signal form and the 'aesthetic sense' proposed by Darwin. Since a receiver bias is sufficient to both initiate and drive ornament or armament exaggeration, without a genetically correlated or even coevolving receiver, this may be the appropriate 'null model' of sexual selection. Thirdly, we focus on the genetic architecture of sexually selected traits. Despite advances in modern molecular techniques, the number and identity of genes underlying performance, display and secondary sexual traits remains largely unknown. In-depth investigations into the genetic basis of sexual dimorphism in the context of long-term field studies will reveal constraints and trajectories of sexually selected trait evolution. Finally, we focus on sexual selection and conflict as drivers of speciation. Population divergence and speciation are often influenced by an interplay between sexual and natural selection. The extent to which sexual selection promotes or counteracts population divergence may vary depending on the genetic architecture of traits as well as the covariance between mating competition and local adaptation. Additionally, post-copulatory processes, such as selection against heterospecific sperm, may influence the importance of sexual selection in speciation. We propose that efforts to resolve these four themes can catalyze conceptual progress in the field of sexual selection, and we offer potential avenues of research to advance this progress.
Collapse
Affiliation(s)
- Willow R. Lindsay
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Staffan Andersson
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Badreddine Bererhi
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Jacob Höglund
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Arild Johnsen
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Charlotta Kvarnemo
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Erica H. Leder
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Jan T. Lifjeld
- Natural History Museum, University of Oslo, Oslo, Norway
| | - Calum E. Ninnes
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
- Department of Entomology and Nematology, University of Florida, Gainesville, FL, United States of America
| | - Mats Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Göteborg, Sweden
| | - Geoff A. Parker
- Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom
| | - Tommaso Pizzari
- Department of Zoology, Edward Grey Institute, University of Oxford, Oxford, United Kingdom
| | - Anna Qvarnström
- Department of Ecology and Genetics, Uppsala University, Uppsala, Sweden
| | - Rebecca J. Safran
- Department of Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, United States of America
| | - Ola Svensson
- School of Natural Sciences, Technology and Environmental Studies, Södertörn University, Huddinge, Sweden
| | - Scott V. Edwards
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA, United States of America
- Gothenburg Centre for Advanced Studies in Science and Technology, Chalmers University of Technology, Göteborg, Sweden
| |
Collapse
|
22
|
O'Connor EA, Westerdahl H, Burri R, Edwards SV. Avian MHC Evolution in the Era of Genomics: Phase 1.0. Cells 2019; 8:E1152. [PMID: 31561531 PMCID: PMC6829271 DOI: 10.3390/cells8101152] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 09/16/2019] [Accepted: 09/20/2019] [Indexed: 12/14/2022] Open
Abstract
Birds are a wonderfully diverse and accessible clade with an exceptional range of ecologies and behaviors, making the study of the avian major histocompatibility complex (MHC) of great interest. In the last 20 years, particularly with the advent of high-throughput sequencing, the avian MHC has been explored in great depth in several dimensions: its ability to explain ecological patterns in nature, such as mating preferences; its correlation with parasite resistance; and its structural evolution across the avian tree of life. Here, we review the latest pulse of avian MHC studies spurred by high-throughput sequencing. Despite high-throughput approaches to MHC studies, substantial areas remain in need of improvement with regard to our understanding of MHC structure, diversity, and evolution. Recent studies of the avian MHC have nonetheless revealed intriguing connections between MHC structure and life history traits, and highlight the advantages of long-term ecological studies for understanding the patterns of MHC variation in the wild. Given the exceptional diversity of birds, their accessibility, and the ease of sequencing their genomes, studies of avian MHC promise to improve our understanding of the many dimensions and consequences of MHC variation in nature. However, significant improvements in assembling complete MHC regions with long-read sequencing will be required for truly transformative studies.
Collapse
Affiliation(s)
| | | | - Reto Burri
- Department of Population Ecology, Institute of Ecology & Evolution, Friedrich Schiller University Jena, 07737 Jena, Germany.
| | - Scott V Edwards
- Department of Organismic and Evolutionary Biology and Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138, USA.
| |
Collapse
|
23
|
Lee W, Plant K, Humburg P, Knight JC. AltHapAlignR: improved accuracy of RNA-seq analyses through the use of alternative haplotypes. Bioinformatics 2019. [PMID: 29514179 PMCID: PMC6041798 DOI: 10.1093/bioinformatics/bty125] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Motivation Reliance on mapping to a single reference haplotype currently limits accurate estimation of allele or haplotype-specific expression using RNA-sequencing, notably in highly polymorphic regions such as the major histocompatibility complex. Results We present AltHapAlignR, a method incorporating alternate reference haplotypes to generate gene- and haplotype-level estimates of transcript abundance for any genomic region where such information is available. We validate using simulated and experimental data to quantify input allelic ratios for major histocompatibility complex haplotypes, demonstrating significantly improved correlation with ground truth estimates of gene counts compared to standard single reference mapping. We apply AltHapAlignR to RNA-seq data from 462 individuals, showing how significant underestimation of expression of the majority of classical human leukocyte antigen genes using conventional mapping can be corrected using AltHapAlignR to allow more accurate quantification of gene expression for individual alleles and haplotypes. Availability and implementation Source code freely available at https://github.com/jknightlab/AltHapAlignR. Supplementary information Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
- Wanseon Lee
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Katharine Plant
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Peter Humburg
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Julian C Knight
- Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| |
Collapse
|
24
|
Ragupathy S, Faller AC, Shanmughanandhan D, Kesanakurti P, Shaanker RU, Ravikanth G, Sathishkumar R, Mathivanan N, Song J, Han J, Newmaster S. Exploring DNA quantity and quality from raw materials to botanical extracts. Heliyon 2019; 5:e01935. [PMID: 31245647 PMCID: PMC6582161 DOI: 10.1016/j.heliyon.2019.e01935] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 05/23/2019] [Accepted: 06/06/2019] [Indexed: 12/02/2022] Open
Abstract
OBJECTIVES The aim of this study was to explore the variability in DNA quality and quantity along a gradient of industrial processing of botanical ingredients from raw materials to extracts. METHODS A data matrix was assembled for 1242 botanical ingredient samples along a gradient of industrial processing commonly used in the Natural Health Product (NHP) industry. Multivariate statistics was used to explore dependant variables for quality and quantity. The success of attaining a positive DNA test result along a gradient of industrial processing was compared among four biotechnologies: DNA barcoding, NGS, Sanger sequencing and qPCR. RESULTS There was considerable variance in DNA quality and quantity among the samples, which could be interpreted along a gradient from raw materials with greater quantities (50-120 ng/μL) of DNA and longer DNA (400-500bp) sequences to extracts, which were characterized by lower quantities (0.1-10.0 ng/μL) and short fragments (50-150bp). CONCLUSIONS Targeted molecular diagnostic tests for species identity can be used in the NHP industry for raw and processed samples. Non-targeted tests or the use of NGS for any identity test needs considerable research and development and must be validated before it can be used in commercial operations as these methods are subject to considerable risk of false negative and positive results. Proper use of these tools can be used to ensure ingredient authenticity, and to avert adulteration, and contamination with plants that are a health concern. Lastly these tools can be used to prevent the exploitation of rare herbal species and the harvesting of native biodiversity for commercial purposes.
Collapse
Affiliation(s)
- Subramanyam Ragupathy
- NHP Research Alliance, College of Biological Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Adam C. Faller
- NHP Research Alliance, College of Biological Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Dhivya Shanmughanandhan
- NHP Research Alliance, College of Biological Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Prasad Kesanakurti
- NHP Research Alliance, College of Biological Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - R. Uma Shaanker
- Department of Crop Physiology and School of Ecology and Conservation, University of Agricultural Sciences, GKVK, Bangalore, 560065, India
| | - Gudasalamani Ravikanth
- Conservation Genetics Lab, Ashoka Trust for Research in Ecology and the Environment (ATREE), Royal Enclave, Srirampura, Jakkur PO, Bengaluru, 560064, India
| | - Ramalingam Sathishkumar
- Plant Genetic Engineering Laboratory, Department of Biotechnology, Bharathiar University, Coimbatore, Tamil Nadu, 641046, India
| | - Narayanasamy Mathivanan
- Centre for Advanced Studies in Botany, University of Madras Guindy Campus, Chennai, 600 025, Tamil Nadu, India
| | - Jingyuan Song
- Engineering Research Center of Traditional Chinese Medicine Resource, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100193, China
| | - Jianping Han
- Engineering Research Center of Traditional Chinese Medicine Resource, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100193, China
| | - Steven Newmaster
- NHP Research Alliance, College of Biological Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| |
Collapse
|
25
|
Thilliez GJA, Armstrong MR, Lim T, Baker K, Jouet A, Ward B, van Oosterhout C, Jones JDG, Huitema E, Birch PRJ, Hein I. Pathogen enrichment sequencing (PenSeq) enables population genomic studies in oomycetes. THE NEW PHYTOLOGIST 2019; 221:1634-1648. [PMID: 30288743 PMCID: PMC6492278 DOI: 10.1111/nph.15441] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/13/2018] [Indexed: 05/11/2023]
Abstract
The oomycete pathogens Phytophthora infestans and P. capsici cause significant crop losses world-wide, threatening food security. In each case, pathogenicity factors, called RXLR effectors, contribute to virulence. Some RXLRs are perceived by resistance proteins to trigger host immunity, but our understanding of the demographic processes and adaptive evolution of pathogen virulence remains poor. Here, we describe PenSeq, a highly efficient enrichment sequencing approach for genes encoding pathogenicity determinants which, as shown for the infamous potato blight pathogen Phytophthora infestans, make up < 1% of the entire genome. PenSeq facilitates the characterization of allelic diversity in pathogen effectors, enabling evolutionary and population genomic analyses of Phytophthora species. Furthermore, PenSeq enables the massively parallel identification of presence/absence variations and sequence polymorphisms in key pathogen genes, which is a prerequisite for the efficient deployment of host resistance genes. PenSeq represents a cost-effective alternative to whole-genome sequencing and addresses crucial limitations of current plant pathogen population studies, which are often based on selectively neutral markers and consequently have limited utility in the analysis of adaptive evolution. The approach can be adapted to diverse microbes and pathogens.
Collapse
Affiliation(s)
- Gaetan J. A. Thilliez
- Cell and Molecular SciencesThe James Hutton InstituteErrol Road, InvergowrieDundeeDD2 5DAUK
- Division of Plant Sciences at the James Hutton InstituteSchool of Life SciencesUniversity of DundeeDundeeDD2 5DAUK
| | - Miles R. Armstrong
- Cell and Molecular SciencesThe James Hutton InstituteErrol Road, InvergowrieDundeeDD2 5DAUK
| | - Tze‐Yin Lim
- Information and Computational SciencesThe James Hutton InstituteDundeeDD2 5DAUK
| | - Katie Baker
- Information and Computational SciencesThe James Hutton InstituteDundeeDD2 5DAUK
| | - Agathe Jouet
- The Sainsbury LaboratoryNorwich Research ParkNorwichNR4 7GJUK
| | - Ben Ward
- The Earlham InstituteNorwich Research ParkNorwichNR4 7UHUK
| | | | | | - Edgar Huitema
- Division of Plant Sciences at the James Hutton InstituteSchool of Life SciencesUniversity of DundeeDundeeDD2 5DAUK
| | - Paul R. J. Birch
- Cell and Molecular SciencesThe James Hutton InstituteErrol Road, InvergowrieDundeeDD2 5DAUK
- Division of Plant Sciences at the James Hutton InstituteSchool of Life SciencesUniversity of DundeeDundeeDD2 5DAUK
| | - Ingo Hein
- Cell and Molecular SciencesThe James Hutton InstituteErrol Road, InvergowrieDundeeDD2 5DAUK
- Division of Plant Sciences at the James Hutton InstituteSchool of Life SciencesUniversity of DundeeDundeeDD2 5DAUK
| |
Collapse
|
26
|
Belasen AM, Bletz MC, Leite DDS, Toledo LF, James TY. Long-Term Habitat Fragmentation Is Associated With Reduced MHC IIB Diversity and Increased Infections in Amphibian Hosts. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2018.00236] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
27
|
Hacking J, Bradford T, Pierce K, Gardner M. De novo genotyping of the major histocompatibility complex in an Australian dragon lizard, Ctenophorus decresii. T ROY SOC SOUTH AUST 2018. [DOI: 10.1080/03721426.2018.1542259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Jessica Hacking
- College of Science and Engineering, Flinders University, Bedford Park, Australia
| | - Tessa Bradford
- College of Science and Engineering, Flinders University, Bedford Park, Australia
- Evolutionary Biology Unit, South Australian Museum, Adelaide, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, Australia
| | - Kelly Pierce
- College of Science and Engineering, Flinders University, Bedford Park, Australia
| | - Michael Gardner
- College of Science and Engineering, Flinders University, Bedford Park, Australia
- Evolutionary Biology Unit, South Australian Museum, Adelaide, Australia
| |
Collapse
|
28
|
Xia W, Xiao Z, Cao P, Zhang Y, Du K, Wang N. Construction of a high-density genetic map and its application for leaf shape QTL mapping in poplar. PLANTA 2018; 248:1173-1185. [PMID: 30088086 DOI: 10.1007/s00425-018-2958-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 07/17/2018] [Indexed: 05/12/2023]
Abstract
High-quality and dense genetic maps were constructed, and leaf shape variation was dissected by QTL mapping in poplar. Species in the genus Populus, also known as poplars, are important woody species and considered model plants for perennial trees. High-density genetic maps are valuable genomic resources for population genetics. Here, we generated a high-quality and dense genetic map for an F1 poplar population using high-throughput NGS-based genotyping. A total of 92,097 high-quality SNP markers were developed by stringent filtering and identification. In total, 889 and 1650 SNPs formed the female and male genetic maps, respectively. To test the application of the genetic maps, QTL mapping of leaf shape was conducted for this F1 population. A total of nine parameters were scored for leaf shape variation in three different environments. Combining genetic maps and measurements of the nine leaf shape parameters, we mapped a total of 42 significant QTLs. The highest LOD score of all QTLs was 9.2, and that QTL explained the most (15.13%) trait variation. A total of nine QTLs could be detected in at least two environments, and they were located in two genomic regions. Within these two QTL regions, some candidate genes for regulating leaf shape were predicted through functional annotation. The successful mapping of leaf shape QTLs demonstrated the utility of our genetic maps. According to the performance of this study, we were able to provide high-quality and dense genetic maps and dissect the leaf shape variation in poplar.
Collapse
Affiliation(s)
- Wenxiu Xia
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zheng'ang Xiao
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Pei Cao
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yan Zhang
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Kebing Du
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Nian Wang
- College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
- Hubei Engineering Technology Research Center for Forestry Information, Huazhong Agricultural University, Wuhan, 430070, China.
| |
Collapse
|
29
|
Vanessa Huml J, Taylor MI, Edwin Harris W, Sen R, Ellis JS. Neutral variation does not predict immunogenetic variation in the European grayling (Thymallus thymallus)-implications for management. Mol Ecol 2018; 27:4157-4173. [PMID: 30194888 DOI: 10.1111/mec.14864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 08/21/2018] [Accepted: 08/29/2018] [Indexed: 11/28/2022]
Abstract
Preservation of genetic diversity is critical to successful conservation, and there is increasing demand for the inclusion of ecologically meaningful genetic information in management decisions. Supportive breeding programmes are increasingly implemented to combat declines in many species, yet their effect on adaptive genetic variation is understudied. This is despite the fact that supportive breeding may interfere with natural evolutionary processes. Here, we assessed the performance of neutral and adaptive markers (major histocompatibility complex; MHC) to inform management of European grayling (Thymallus thymallus), which routinely involves supplementation of natural populations with hatchery-reared fish (stocking). This study is the first to characterize MH II DAA and DAB loci in grayling and to investigate immune genetic variation in relation to management practice in this species. High-throughput Illumina sequencing of "introduced," "stocked native" and "non-stocked native" populations revealed significantly higher levels of allelic richness and heterozygosity for MH markers than microsatellites exclusively in non-stocked native populations. Likewise, significantly lower differentiation at the MH II than for microsatellites was apparent when considering non-stocked native populations, but not stocked populations. We developed a simulation model to test the effects of relaxation of selection during the early life stage within captivity. Dependent on the census population size and stocking intensity, there may be long-term effects of stocking on MH II, but not neutral genetic diversity. This is consistent with our empirical results. This study highlights the necessity for considering adaptive genetic variation in conservation decisions and raises concerns about the efficiency of stocking as a management practice.
Collapse
Affiliation(s)
- J Vanessa Huml
- School of Science & Environment, Manchester Metropolitan University, Manchester, UK.,School of Biological and Marine Sciences, University of Plymouth, Plymouth, UK
| | - Martin I Taylor
- School of Biological Sciences, University of East Anglia, Norwich, UK
| | - W Edwin Harris
- School of Science & Environment, Manchester Metropolitan University, Manchester, UK
| | - Robin Sen
- School of Science & Environment, Manchester Metropolitan University, Manchester, UK
| | - Jonathan S Ellis
- School of Biological and Marine Sciences, University of Plymouth, Plymouth, UK
| |
Collapse
|
30
|
Buckley J, Holub EB, Koch MA, Vergeer P, Mable BK. Restriction associated DNA-genotyping at multiple spatial scales in Arabidopsis lyrata reveals signatures of pathogen-mediated selection. BMC Genomics 2018; 19:496. [PMID: 29945543 PMCID: PMC6020377 DOI: 10.1186/s12864-018-4806-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Accepted: 05/18/2018] [Indexed: 11/22/2022] Open
Abstract
Background Genome scans based on outlier analyses have revolutionized detection of genes involved in adaptive processes, but reports of some forms of selection, such as balancing selection, are still limited. It is unclear whether high throughput genotyping approaches for identification of single nucleotide polymorphisms have sufficient power to detect modes of selection expected to result in reduced genetic differentiation among populations. In this study, we used Arabidopsis lyrata to investigate whether signatures of balancing selection can be detected based on genomic smoothing of Restriction Associated DNA sequencing (RAD-seq) data. We compared how different sampling approaches (both within and between subspecies) and different background levels of polymorphism (inbreeding or outcrossing populations) affected the ability to detect genomic regions showing key signatures of balancing selection, specifically elevated polymorphism, reduced differentiation and shifts towards intermediate allele frequencies. We then tested whether candidate genes associated with disease resistance (R-gene analogs) were detected more frequently in these regions compared to other regions of the genome. Results We found that genomic regions showing elevated polymorphism contained a significantly higher density of R-gene analogs predicted to be under pathogen-mediated selection than regions of non-elevated polymorphism, and that many of these also showed evidence for an intermediate site-frequency spectrum based on Tajima’s D. However, we found few genomic regions that showed both elevated polymorphism and reduced FST among populations, despite strong background levels of genetic differentiation among populations. This suggests either insufficient power to detect the reduced population structure predicted for genes under balancing selection using sparsely distributed RAD markers, or that other forms of diversifying selection are more common for the R-gene analogs tested. Conclusions Genome scans based on a small number of individuals sampled from a wide range of populations were sufficient to confirm the relative scarcity of signatures of balancing selection across the genome, but also identified new potential disease resistance candidates within genomic regions showing signatures of balancing selection that would be strong candidates for further sequencing efforts. Electronic supplementary material The online version of this article (10.1186/s12864-018-4806-7) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- James Buckley
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK. .,Adaptation to a Changing Environment, Institute of Integrative Biology, ETH Zürich, CH-8092, Zürich, Switzerland.
| | - Eric B Holub
- School of Life Sciences, Warwick Crop Centre, University of Warwick, Wellesbourne, CV35 9EF, UK
| | - Marcus A Koch
- Centre for Organismal Studies (COS) Heidelberg, Biodiversity and Plant Systematics, Heidelberg University, D69120, Heidelberg, Germany
| | - Philippine Vergeer
- Plant Ecology and Nature Conservation Group, Wageningen University, P.O.Box 47, 6700, AA, Wageningen, The Netherlands
| | - Barbara K Mable
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| |
Collapse
|
31
|
Rekdal SL, Anmarkrud JA, Johnsen A, Lifjeld JT. Genotyping strategy matters when analyzing hypervariable major histocompatibility complex-Experience from a passerine bird. Ecol Evol 2018; 8:1680-1692. [PMID: 29435243 PMCID: PMC5792522 DOI: 10.1002/ece3.3757] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/30/2017] [Accepted: 12/04/2017] [Indexed: 12/26/2022] Open
Abstract
Genotyping of classical major histocompatibility complex (MHC) genes is challenging when they are hypervariable and occur in multiple copies. In this study, we used several different approaches to genotype the moderately variable MHC class I exon 3 (MHCIe3) and the highly polymorphic MHC class II exon 2 (MHCIIβe2) in the bluethroat (Luscinia svecica). Two family groups (eight individuals) were sequenced in replicates at both markers using Ion Torrent technology with both a single- and a dual-indexed primer structure. Additionally, MHCIIβe2 was sequenced on Illumina MiSeq. Allele calling was conducted by modifications of the pipeline developed by Sommer et al. (BMC Genomics, 14, 2013, 542) and the software AmpliSAS. While the different genotyping strategies gave largely consistent results for MHCIe3, with a maximum of eight alleles per individual, MHCIIβe2 was remarkably complex with a maximum of 56 MHCIIβe2 alleles called for one individual. Each genotyping strategy detected on average 50%-82% of all MHCIIβe2 alleles per individual, but dropouts were largely allele-specific and consistent within families for each strategy. The discrepancies among approaches indicate PCR biases caused by the platform-specific primer tails. Further, AmpliSAS called fewer alleles than the modified Sommer pipeline. Our results demonstrate that allelic dropout is a significant problem when genotyping the hypervariable MHCIIβe2. As these genotyping errors are largely nonrandom and method-specific, we caution against comparing genotypes across different genotyping strategies. Nevertheless, we conclude that high-throughput approaches provide a major advance in the challenging task of genotyping hypervariable MHC loci, even though they may not reveal the complete allelic repertoire.
Collapse
|
32
|
Sebastian A, Migalska M, Biedrzycka A. AmpliSAS and AmpliHLA: Web Server Tools for MHC Typing of Non-Model Species and Human Using NGS Data. Methods Mol Biol 2018; 1802:249-273. [PMID: 29858815 DOI: 10.1007/978-1-4939-8546-3_18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
AmpliSAS and AmpliHLA are web server tools for automatic genotyping of MHC genes from high-throughput sequencing data. AmpliSAS is designed specifically to analyze amplicon sequencing data from non-model species and it is able to perform de-novo genotyping without any previous knowledge of the reference alleles. AmpliHLA is a human-specific version, it performs HLA typing by comparing sequenced variants against human reference alleles from the IMGT/HLA database. Here we describe four genotyping protocols: the first two use amplicon sequencing data to genotype the MHC genes of a passerine bird and human respectively; the third and fourth present the HLA typing of a human cell line starting from RNA and exome sequencing data respectively.
Collapse
Affiliation(s)
- Alvaro Sebastian
- Sixth Researcher, Poznan, Poland. .,Instituto Aragonés de Empleo (INAEM), Zaragoza, Spain. .,Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland.
| | - Magdalena Migalska
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | | |
Collapse
|
33
|
Lighten J, Papadopulos AST, Mohammed RS, Ward BJ, G Paterson I, Baillie L, Bradbury IR, Hendry AP, Bentzen P, van Oosterhout C. Evolutionary genetics of immunological supertypes reveals two faces of the Red Queen. Nat Commun 2017; 8:1294. [PMID: 29101318 PMCID: PMC5670221 DOI: 10.1038/s41467-017-01183-2] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 08/23/2017] [Indexed: 11/09/2022] Open
Abstract
Red Queen host-parasite co-evolution can drive adaptations of immune genes by positive selection that erodes genetic variation (Red Queen arms race) or results in a balanced polymorphism (Red Queen dynamics) and long-term preservation of genetic variation (trans-species polymorphism). These two Red Queen processes are opposite extremes of the co-evolutionary spectrum. Here we show that both Red Queen processes can operate simultaneously by analysing the major histocompatibility complex (MHC) in guppies (Poecilia reticulata and P. obscura) and swamp guppies (Micropoecilia picta). Sub-functionalisation of MHC alleles into 'supertypes' explains how polymorphisms persist during rapid host-parasite co-evolution. Simulations show the maintenance of supertypes as balanced polymorphisms, consistent with Red Queen dynamics, whereas alleles within supertypes are subject to positive selection in a Red Queen arms race. Building on the divergent allele advantage hypothesis, we show that functional aspects of allelic diversity help to elucidate the evolution of polymorphic genes involved in Red Queen co-evolution.
Collapse
Affiliation(s)
- Jackie Lighten
- School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK.
| | - Alexander S T Papadopulos
- Molecular Ecology and Fisheries Genetics Laboratory, Environment Centre Wales, School of Biological Sciences, Bangor University, Bangor, LL57 2UW, UK
| | - Ryan S Mohammed
- Department of Life Sciences, The University of the West Indies, St Augustine, Trinidad and Tobago
| | - Ben J Ward
- Earlham Institute, Norwich Research Park Innovation Centre, Colney Lane, Norwich, NR4 7UZ, UK
| | - Ian G Paterson
- Marine Gene Probe Laboratory, Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS, Canada, B3H 4R2
| | - Lyndsey Baillie
- Michael Smith Laboratories, University of British Columbia, 2185 East Mall, Vancouver, BC, Canada, V6T 1Z4
| | - Ian R Bradbury
- Marine Gene Probe Laboratory, Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS, Canada, B3H 4R2.,Science Branch, Department of Fisheries and Oceans Canada, 80 East White Hills Road, St. John's, NL, Canada, A1C 5X1
| | - Andrew P Hendry
- McGill University, 859 Sherbrooke Street West, Montreal, QC, Canada, H3A 0C4.,Redpath Museum, McGill University, 859 Sherbrooke Street West, Montreal, QC, Canada, H3A 0C4
| | - Paul Bentzen
- Marine Gene Probe Laboratory, Department of Biology, Dalhousie University, 1355 Oxford Street, Halifax, NS, Canada, B3H 4R2
| | - Cock van Oosterhout
- School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, NR4 7TJ, UK.
| |
Collapse
|
34
|
Kumar G, Chaudhary KK, Misra K, Tripathi A. Next-Generation Sequencing for Drug Designing and Development: An Omics Approach for Cancer Treatment. INT J PHARMACOL 2017. [DOI: 10.3923/ijp.2017.709.723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
35
|
Santonastaso T, Lighten J, van Oosterhout C, Jones KL, Foufopoulos J, Anthony NM. The effects of historical fragmentation on major histocompatibility complex class II β and microsatellite variation in the Aegean island reptile, Podarcis erhardii. Ecol Evol 2017; 7:4568-4581. [PMID: 28690787 PMCID: PMC5496512 DOI: 10.1002/ece3.3022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 03/16/2017] [Accepted: 03/27/2017] [Indexed: 01/29/2023] Open
Abstract
The major histocompatibility complex (MHC) plays a key role in disease resistance and is the most polymorphic gene region in vertebrates. Although habitat fragmentation is predicted to lead to a loss in MHC variation through drift, the impact of other evolutionary forces may counter this effect. Here we assess the impact of selection, drift, migration, and recombination on MHC class II and microsatellite variability in 14 island populations of the Aegean wall lizard Podarcis erhardii. Lizards were sampled from islands within the Cyclades (Greece) formed by rising sea levels as the last glacial maximum approximately 20,000 before present. Bathymetric data were used to determine the area and age of each island, allowing us to infer the corresponding magnitude and timing of genetic bottlenecks associated with island formation. Both MHC and microsatellite variation were positively associated with island area, supporting the hypothesis that drift governs neutral and adaptive variation in this system. However, MHC but not microsatellite variability declined significantly with island age. This discrepancy is likely due to the fact that microsatellites attain mutation‐drift equilibrium more rapidly than MHC. Although we detected signals of balancing selection, recombination and migration, the effects of these evolutionary processes appeared negligible relative to drift. This study demonstrates how land bridge islands can provide novel insights into the impact of historical fragmentation on genetic diversity as well as help disentangle the effects of different evolutionary forces on neutral and adaptive diversity.
Collapse
Affiliation(s)
- Trent Santonastaso
- Department of Biological Sciences University of New Orleans New Orleans LA USA
| | - Jackie Lighten
- School of Environmental Sciences University of East Anglia Norwich Research Park Norwich UK
| | - Cock van Oosterhout
- School of Environmental Sciences University of East Anglia Norwich Research Park Norwich UK
| | - Kenneth L Jones
- Department of Biochemistry and Molecular Genetics University of Colorado Denver School of Medicine Denver CO USA
| | - Johannes Foufopoulos
- School of the Environment and Sustainability University of Michigan Ann Arbor MI USA
| | - Nicola M Anthony
- Department of Biological Sciences University of New Orleans New Orleans LA USA
| |
Collapse
|
36
|
Hofmann MJ, Bracamonte SE, Eizaguirre C, Barluenga M. Molecular characterization of MHC class IIB genes of sympatric Neotropical cichlids. BMC Genet 2017; 18:15. [PMID: 28201988 PMCID: PMC5310070 DOI: 10.1186/s12863-017-0474-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/13/2017] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The Major Histocompatibility Complex (MHC) is a key component of the adaptive immune system of all vertebrates and consists of the most polymorphic genes known to date. Due to this complexity, however, MHC remains to be characterized in many species including any Neotropical cichlid fish. Neotropical crater lake cichlids are ideal models to study evolutionary processes as they display one of the most convincing examples of sympatric and repeated parallel radiation events within and among isolated crater lakes. RESULTS Here, we characterized the genes of MHC class IIB chain of the Midas cichlid species complex (Amphilophus cf. citrinellus) including fish from five lakes in Nicaragua. We designed 19 new specific primers anchored in a stepwise fashion in order to detect all alleles present. We obtained 866 genomic DNA (gDNA) sequences from thirteen individuals and 756 additional sequences from complementary DNA (cDNA) of seven of those individuals. We identified 69 distinct alleles with up to 25 alleles per individual. We also found considerable intron length variation and mismatches of alleles detected in cDNA and gDNA suggesting that some loci have undergone pseudogenization. Lastly, we created a model of protein structure homology for each allele and identified their key structural components. CONCLUSIONS Overall, the Midas cichlid has one of the most diverse repertoires of MHC class IIB genes known, which could serve as a powerful tool to elucidate the process of divergent radiations, colonization and speciation in sympatry.
Collapse
Affiliation(s)
- Melinda J Hofmann
- Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal, 2, 28006, Madrid, Spain
| | - Seraina E Bracamonte
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Duesternbrooker weg 20, 24105, Kiel, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Müggelseedamm 310, 12587, Berlin, Germany
| | - Christophe Eizaguirre
- GEOMAR Helmholtz Centre for Ocean Research Kiel, Duesternbrooker weg 20, 24105, Kiel, Germany
- Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London, E1 4NS, UK
| | - Marta Barluenga
- Museo Nacional de Ciencias Naturales, CSIC, José Gutiérrez Abascal, 2, 28006, Madrid, Spain.
| |
Collapse
|
37
|
Biedrzycka A, Sebastian A, Migalska M, Westerdahl H, Radwan J. Testing genotyping strategies for ultra-deep sequencing of a co-amplifying gene family: MHC class I in a passerine bird. Mol Ecol Resour 2016; 17:642-655. [DOI: 10.1111/1755-0998.12612] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Revised: 02/10/2016] [Accepted: 08/23/2016] [Indexed: 12/15/2022]
Affiliation(s)
- Aleksandra Biedrzycka
- Institute of Nature Conservation; Polish Academy of Sciences; Al. Mickiewicza 33 31-120 Kraków Poland
| | - Alvaro Sebastian
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznań Poland
| | - Magdalena Migalska
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznań Poland
| | - Helena Westerdahl
- Department of Biology; Lund University; Ecology Building, Sölvegatan 37 223 62 Lund Sweden
| | - Jacek Radwan
- Evolutionary Biology Group; Faculty of Biology; Adam Mickiewicz University; ul. Umultowska 89 61-614 Poznań Poland
| |
Collapse
|
38
|
Migalska M, Sebastian A, Konczal M, Kotlík P, Radwan J. De novo transcriptome assembly facilitates characterisation of fast-evolving gene families, MHC class I in the bank vole (Myodes glareolus). Heredity (Edinb) 2016; 118:348-357. [PMID: 27782121 DOI: 10.1038/hdy.2016.105] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 09/20/2016] [Indexed: 02/07/2023] Open
Abstract
The major histocompatibility complex (MHC) plays a central role in the adaptive immune response and is the most polymorphic gene family in vertebrates. Although high-throughput sequencing has increasingly been used for genotyping families of co-amplifying MHC genes, its potential to facilitate early steps in the characterisation of MHC variation in nonmodel organism has not been fully explored. In this study we evaluated the usefulness of de novo transcriptome assembly in characterisation of MHC sequence diversity. We found that although de novo transcriptome assembly of MHC I genes does not reconstruct sequences of individual alleles, it does allow the identification of conserved regions for PCR primer design. Using the newly designed primers, we characterised MHC I sequences in the bank vole. Phylogenetic analysis of the partial MHC I coding sequence (2-4 exons) of the bank vole revealed a lack of orthology to MHC I of other Cricetidae, consistent with the high gene turnover of this region. The diversity of expressed alleles was characterised using ultra-deep sequencing of the third exon that codes for the peptide-binding region of the MHC molecule. High allelic diversity was demonstrated, with 72 alleles found in 29 individuals. Interindividual variation in the number of expressed loci was found, with the number of alleles per individual ranging from 5 to 14. Strong signatures of positive selection were found for 8 amino acid sites, most of which are inferred to bind antigens in human MHC, indicating conservation of structure despite rapid sequence evolution.
Collapse
Affiliation(s)
- M Migalska
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - A Sebastian
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - M Konczal
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| | - P Kotlík
- Laboratory of Molecular Ecology, Institute of Animal Physiology and Genetics, The Czech Academy of Sciences, Liběchov, Czech Republic
| | - J Radwan
- Evolutionary Biology Group, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
| |
Collapse
|
39
|
Eimes JA, Lee SI, Townsend AK, Jablonski P, Nishiumi I, Satta Y. Early Duplication of a Single MHC IIB Locus Prior to the Passerine Radiations. PLoS One 2016; 11:e0163456. [PMID: 27658204 PMCID: PMC5033386 DOI: 10.1371/journal.pone.0163456] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 09/08/2016] [Indexed: 01/01/2023] Open
Abstract
A key characteristic of MHC genes is the persistence of allelic lineages over macroevolutionary periods, often through multiple speciation events. This phenomenon, known as trans-species polymorphism (TSP), is well documented in several major taxonomic groups, but has less frequently been observed in birds. The order Passeriformes is arguably the most successful terrestrial vertebrate order in terms of diversity of species and ecological range, but the reasons for this success remain unclear. Passerines exhibit the most highly duplicated MHC genes of any major vertebrate taxonomic group, which may generate increased immune response relative to other avian orders with fewer MHC loci. Here, we describe phylogenetic patterns of the MHC IIB in the passerine family Corvidae. Our results indicate wide-spread TSP within this family, with at least four supported MHC IIB allelic lineages that predate speciation by many millions of years. Markov chain Monte Carlo simulations indicate that divergence of these lineages occurred near the time of the divergence of the Passeriformes and other avian orders. We suggest that the current MHC diversity observed in passerines is due in part to the multiple duplication of a single MHC locus, DAB1, early in passerine evolution and that subsequent duplications of these paralogues have contributed to the enormous success of this order by increasing their ability to recognize and mount immune responses to novel pathogens.
Collapse
Affiliation(s)
- John A. Eimes
- Seoul National University, Department of Biological Sciences, Seoul, Korea
| | - Sang-im Lee
- Seoul National University, Institute of Advanced Machines and Design, Seoul, Korea
- * E-mail:
| | - Andrea K. Townsend
- Hamilton College, Department of Biology, Clinton, NY, United States of America
| | - Piotr Jablonski
- Seoul National University, Department of Biological Sciences, Seoul, Korea
| | - Isao Nishiumi
- National Museum of Nature and Science, Department of Zoology, Tsukuba, Japan
| | - Yoko Satta
- The Graduate University for Advanced Studies, Department of Evolutionary Studies of Biosystems, Hayama, Japan
| |
Collapse
|
40
|
Vlček J, Hoeck PEA, Keller LF, Wayhart JP, Dolinová I, Štefka J. Balancing selection and genetic drift create unusual patterns of MHCIIβ variation in Galápagos mockingbirds. Mol Ecol 2016; 25:4757-72. [PMID: 27545344 DOI: 10.1111/mec.13807] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 07/28/2016] [Accepted: 08/08/2016] [Indexed: 01/01/2023]
Abstract
The extracellular subunit of the major histocompatibility complex MHCIIβ plays an important role in the recognition of pathogens and the initiation of the adaptive immune response of vertebrates. It is widely accepted that pathogen-mediated selection in combination with neutral micro-evolutionary forces (e.g. genetic drift) shape the diversity of MHCIIβ, but it has proved difficult to determine the relative effects of these forces. We evaluated the effect of genetic drift and balancing selection on MHCIIβ diversity in 12 small populations of Galápagos mockingbirds belonging to four different species, and one larger population of the Northern mockingbird from the continental USA. After genotyping MHCIIβ loci by high-throughput sequencing, we applied a correlational approach to explore the relationships between MHCIIβ diversity and population size by proxy of island size. As expected when drift predominates, we found a positive effect of population size on the number of MHCIIβ alleles present in a population. However, the number of MHCIIβ alleles per individual and number of supertypes were not correlated with population size. This discrepancy points to an interesting feature of MHCIIβ diversity dynamics: some levels of diversity might be shaped by genetic drift while others are independent and possibly maintained by balancing selection.
Collapse
Affiliation(s)
- Jakub Vlček
- Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic.,Faculty of Science, University of South Bohemia, Branišovská 1670, České Budějovice, Czech Republic
| | - Paquita E A Hoeck
- Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Road, Escondido, CA, 92027, USA
| | - Lukas F Keller
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland
| | - Jessica P Wayhart
- Institute for Conservation Research, San Diego Zoo Global, 15600 San Pasqual Valley Road, Escondido, CA, 92027, USA
| | - Iva Dolinová
- Institute for Nanomaterials, Advanced Technologies and Innovation, Technical University of Liberec, Bendlova 7, Liberec, Czech Republic
| | - Jan Štefka
- Biology Centre CAS, Branišovská 31, 37005, České Budějovice, Czech Republic. .,Faculty of Science, University of South Bohemia, Branišovská 1670, České Budějovice, Czech Republic.
| |
Collapse
|
41
|
Marmesat E, Soriano L, Mazzoni CJ, Sommer S, Godoy JA. PCR Strategies for Complete Allele Calling in Multigene Families Using High-Throughput Sequencing Approaches. PLoS One 2016; 11:e0157402. [PMID: 27294261 PMCID: PMC4905633 DOI: 10.1371/journal.pone.0157402] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 05/27/2016] [Indexed: 11/19/2022] Open
Abstract
The characterization of multigene families with high copy number variation is often approached through PCR amplification with highly degenerate primers to account for all expected variants flanking the region of interest. Such an approach often introduces PCR biases that result in an unbalanced representation of targets in high-throughput sequencing libraries that eventually results in incomplete detection of the targeted alleles. Here we confirm this result and propose two different amplification strategies to alleviate this problem. The first strategy (called pooled-PCRs) targets different subsets of alleles in multiple independent PCRs using different moderately degenerate primer pairs, whereas the second approach (called pooled-primers) uses a custom-made pool of non-degenerate primers in a single PCR. We compare their performance to the common use of a single PCR with highly degenerate primers using the MHC class I of the Iberian lynx as a model. We found both novel approaches to work similarly well and better than the conventional approach. They significantly scored more alleles per individual (11.33 ± 1.38 and 11.72 ± 0.89 vs 7.94 ± 1.95), yielded more complete allelic profiles (96.28 ± 8.46 and 99.50 ± 2.12 vs 63.76 ± 15.43), and revealed more alleles at a population level (13 vs 12). Finally, we could link each allele's amplification efficiency with the primer-mismatches in its flanking sequences and show that ultra-deep coverage offered by high-throughput technologies does not fully compensate for such biases, especially as real alleles may reach lower coverage than artefacts. Adopting either of the proposed amplification methods provides the opportunity to attain more complete allelic profiles at lower coverages, improving confidence over the downstream analyses and subsequent applications.
Collapse
Affiliation(s)
- Elena Marmesat
- Department of Integrative Ecology, Estación Biológica de Doñana (CSIC), Sevilla, Spain
| | - Laura Soriano
- Department of Integrative Ecology, Estación Biológica de Doñana (CSIC), Sevilla, Spain
| | - Camila J. Mazzoni
- Berlin Center for Genomics in Biodiversity Research (BeGenDiv), Berlin, Germany
- Leibniz Institute for Zoo and Wildlife Research (IZW), Berlin, Germany
| | - Simone Sommer
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
| | - José A. Godoy
- Department of Integrative Ecology, Estación Biológica de Doñana (CSIC), Sevilla, Spain
- * E-mail:
| |
Collapse
|
42
|
Gaigher A, Burri R, Gharib WH, Taberlet P, Roulin A, Fumagalli L. Family-assisted inference of the genetic architecture of major histocompatibility complex variation. Mol Ecol Resour 2016; 16:1353-1364. [DOI: 10.1111/1755-0998.12537] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 04/07/2016] [Accepted: 04/18/2016] [Indexed: 12/13/2022]
Affiliation(s)
- A. Gaigher
- Laboratory for Conservation Biology; Department of Ecology and Evolution; University of Lausanne; Biophore Lausanne CH-1015 Switzerland
| | - R. Burri
- Department of Evolutionary Biology; Uppsala University; Norbyvägen 18D SE-752 36 Uppsala Sweden
| | - W. H. Gharib
- Interfaculty Bioinformatics Unit; University of Bern; CH-3012 Bern Switzerland
| | - P. Taberlet
- CNRS; Laboratoire d'Ecologie Alpine (LECA); 38000 Grenoble France
- Laboratoire d'Ecologie Alpine (LECA); University of Grenoble Alpes; 38000 Grenoble France
| | - A. Roulin
- Laboratory for Conservation Biology; Department of Ecology and Evolution; University of Lausanne; Biophore Lausanne CH-1015 Switzerland
| | - L. Fumagalli
- Laboratory for Conservation Biology; Department of Ecology and Evolution; University of Lausanne; Biophore Lausanne CH-1015 Switzerland
| |
Collapse
|
43
|
Jaeger CP, Duvall MR, Swanson BJ, Phillips CA, Dreslik MJ, Baker SJ, King RB. Microsatellite and major histocompatibility complex variation in an endangered rattlesnake, the Eastern Massasauga (Sistrurus catenatus). Ecol Evol 2016; 6:3991-4003. [PMID: 27516858 PMCID: PMC4874855 DOI: 10.1002/ece3.2159] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 03/30/2016] [Accepted: 04/01/2016] [Indexed: 01/18/2023] Open
Abstract
Genetic diversity is fundamental to maintaining the long-term viability of populations, yet reduced genetic variation is often associated with small, isolated populations. To examine the relationship between demography and genetic variation, variation at hypervariable loci (e.g., microsatellite DNA loci) is often measured. However, these loci are selectively neutral (or near neutral) and may not accurately reflect genomewide variation. Variation at functional trait loci, such as the major histocompatibility complex (MHC), can provide a better assessment of adaptive genetic variation in fragmented populations. We compared patterns of microsatellite and MHC variation across three Eastern Massasauga (Sistrurus catenatus) populations representing a gradient of demographic histories to assess the relative roles of natural selection and genetic drift. Using 454 deep amplicon sequencing, we identified 24 putatively functional MHC IIB exon 2 alleles belonging to a minimum of six loci. Analysis of synonymous and nonsynonymous substitution rates provided evidence of historical positive selection at the nucleotide level, and Tajima's D provided support for balancing selection in each population. As predicted, estimates of microsatellite allelic richness, observed, heterozygosity, and expected heterozygosity varied among populations in a pattern qualitatively consistent with demographic history and abundance. While MHC allelic richness at the population and individual levels revealed similar trends, MHC nucleotide diversity was unexpectedly high in the smallest population. Overall, these results suggest that genetic variation in the Eastern Massasauga populations in Illinois has been shaped by multiple evolutionary mechanisms. Thus, conservation efforts should consider both neutral and functional genetic variation when managing captive and wild Eastern Massasauga populations.
Collapse
Affiliation(s)
- Collin P. Jaeger
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
| | - Melvin R. Duvall
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
| | - Bradley J. Swanson
- Department of BiologyCentral Michigan UniversityMt. PleasantMichigan48859
| | - Christopher A. Phillips
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Michael J. Dreslik
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Sarah J. Baker
- Illinois Natural History SurveyUniversity of Illinois Urbana‐ChampaignChampaignIllinois61820
| | - Richard B. King
- Department of Biological SciencesNorthern Illinois UniversityDeKalbIllinois60115
| |
Collapse
|
44
|
Baltazar-Soares M, Bracamonte SE, Bayer T, Chain FJ, Hanel R, Harrod C, Eizaguirre C. Evaluating the adaptive potential of the European eel: is the immunogenetic status recovering? PeerJ 2016; 4:e1868. [PMID: 27077000 PMCID: PMC4830236 DOI: 10.7717/peerj.1868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 03/09/2016] [Indexed: 02/03/2023] Open
Abstract
The recent increased integration of evolutionary theory into conservation programs has greatly improved our ability to protect endangered species. A common application of such theory links population dynamics and indices of genetic diversity, usually estimated from neutrally evolving markers. However, some studies have suggested that highly polymorphic adaptive genes, such as the immune genes of the Major Histocompatibility Complex (MHC), might be more sensitive to fluctuations in population dynamics. As such, the combination of neutrally- and adaptively-evolving genes may be informative in populations where reductions in abundance have been documented. The European eel (Anguilla anguilla) underwent a drastic and well-reported decline in abundance in the late 20th century and still displays low recruitment. Here we compared genetic diversity indices estimated from neutral (mitochondrial DNA and microsatellites) and adaptive markers (MHC) between two distinct generations of European eels. Our results revealed a clear discrepancy between signatures obtained for each class of markers. Although mtDNA and microsatellites showed no changes in diversity between the older and the younger generations, MHC diversity revealed a contemporary drop followed by a recent increase. Our results suggest ongoing gain of MHC genetic diversity resulting from the interplay between drift and selection and ultimately increasing the adaptive potential of the species.
Collapse
Affiliation(s)
- Miguel Baltazar-Soares
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - Seraina E. Bracamonte
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
- Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
| | - Till Bayer
- Evolutionary Ecology of Marine Fishes, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | | | | | - Chris Harrod
- Universidad de Antofagasta, Instituto de Ciencias Naturales Alexander von Humboldt, Antofagasta, Chile
| | - Christophe Eizaguirre
- School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
| |
Collapse
|
45
|
Faulks LK, Östman Ö. Adaptive major histocompatibility complex (MHC) and neutral genetic variation in two native Baltic Sea fishes (perch Perca fluviatilis and zander Sander lucioperca) with comparisons to an introduced and disease susceptible population in Australia (P. fluviatilis): assessing the risk of disease epidemics. JOURNAL OF FISH BIOLOGY 2016; 88:1564-1583. [PMID: 26940068 DOI: 10.1111/jfb.12930] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 01/29/2016] [Indexed: 06/05/2023]
Abstract
This study assessed the major histocompatibility complex (MHC) and neutral genetic variation and structure in two percid species, perch Perca fluviatilis and zander Sander lucioperca, in a unique brackish ecosystem, the Baltic Sea. In addition, to assess the importance of MHC diversity to disease susceptibility in these populations, comparisons were made to an introduced, disease susceptible, P. fluviatilis population in Australia. Eighty-three MHC class II B exon 2 variants were amplified: 71 variants from 92 P. fluviatilis samples, and 12 variants from 82 S. lucioperca samples. Microsatellite and MHC data revealed strong spatial genetic structure in S. lucioperca, but not P. fluviatilis, across the Baltic Sea. Both microsatellite and MHC data showed higher levels of genetic diversity in P. fluviatilis from the Baltic Sea compared to Australia, which may have facilitated the spread of an endemic virus, EHNV in the Australian population. The relatively high levels of genetic variation in the Baltic Sea populations, together with spatial genetic structure, however, suggest that there currently seems to be little risk of disease epidemics in this system. To ensure this remains the case in the face of ongoing environmental changes, fisheries and habitat disturbance, the conservation of local-scale genetic variation is recommended.
Collapse
Affiliation(s)
- L K Faulks
- Department of Ecology and Genetics - Animal Ecology, Uppsala University, Norbyvägen 18D, 75236, Uppsala, Sweden
| | - Ö Östman
- Department of Aquatic Resources - Institute of Coastal Research, Swedish University of Agricultural Sciences, Skolvägen 6, 74242, Öregrund, Sweden
| |
Collapse
|
46
|
Grogan KE, McGinnis GJ, Sauther ML, Cuozzo FP, Drea CM. Next-generation genotyping of hypervariable loci in many individuals of a non-model species: technical and theoretical implications. BMC Genomics 2016; 17:204. [PMID: 26957424 PMCID: PMC4782575 DOI: 10.1186/s12864-016-2503-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 02/18/2016] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Across species, diversity at the Major Histocompatibility Complex (MHC) is critical to disease resistance and population health; however, use of MHC diversity to quantify the genetic health of populations has been hampered by the extreme variation found in MHC genes. Next generation sequencing (NGS) technology generates sufficient data to genotype even the most diverse species, but workflows for distinguishing artifacts from alleles are still under development. We used NGS to evaluate the MHC diversity of over 300 captive and wild ring-tailed lemurs (Lemur catta: Primates: Mammalia). We modified a published workflow to address errors that arise from deep sequencing individuals and tested for evidence of selection at the most diverse MHC genes. RESULTS In addition to evaluating the accuracy of 454 Titanium and Ion Torrent PGM for genotyping large populations at hypervariable genes, we suggested modifications to improve current methods of allele calling. Using these modifications, we genotyped 302 out of 319 individuals, obtaining an average sequencing depth of over 1000 reads per amplicon. We identified 55 MHC-DRB alleles, 51 of which were previously undescribed, and provide the first sequences of five additional MHC genes: DOA, DOB, DPA, DQA, and DRA. The additional five MHC genes had one or two alleles each with little sequence variation; however, the 55 MHC-DRB alleles showed a high dN/dS ratio and trans-species polymorphism, indicating a history of positive selection. Because each individual possessed 1-7 MHC-DRB alleles, we suggest that ring-tailed lemurs have four, putatively functional, MHC-DRB copies. CONCLUSIONS In the future, accurate genotyping methods for NGS data will be critical to assessing genetic variation in non-model species. We recommend that future NGS studies increase the proportion of replicated samples, both within and across platforms, particularly for hypervariable genes like the MHC. Quantifying MHC diversity within non-model species is the first step to assessing the relationship of genetic diversity at functional loci to individual fitness and population viability. Owing to MHC-DRB diversity and copy number, ring-tailed lemurs may serve as an ideal model for estimating the interaction between genetic diversity, fitness, and environment, especially regarding endangered species.
Collapse
Affiliation(s)
- Kathleen E Grogan
- University Program in Ecology, Duke University, Durham, NC, USA.
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA.
- Emory University, Room 2006 O. Wayne Rollins Research Center, 1510 Clifton Rd NE, Atlanta, GA, 30322, USA.
| | | | - Michelle L Sauther
- Department of Anthropology, University of Colorado-Boulder, Boulder, CO, USA
| | - Frank P Cuozzo
- Department of Anthropology, University of North Dakota, Grand Forks, ND, USA
| | - Christine M Drea
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Biology, Duke University, Durham, USA
| |
Collapse
|
47
|
Selection on Coding and Regulatory Variation Maintains Individuality in Major Urinary Protein Scent Marks in Wild Mice. PLoS Genet 2016; 12:e1005891. [PMID: 26938775 PMCID: PMC4777540 DOI: 10.1371/journal.pgen.1005891] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 01/31/2016] [Indexed: 01/17/2023] Open
Abstract
Recognition of individuals by scent is widespread across animal taxa. Though animals can often discriminate chemical blends based on many compounds, recent work shows that specific protein pheromones are necessary and sufficient for individual recognition via scent marks in mice. The genetic nature of individuality in scent marks (e.g. coding versus regulatory variation) and the evolutionary processes that maintain diversity are poorly understood. The individual signatures in scent marks of house mice are the protein products of a group of highly similar paralogs in the major urinary protein (Mup) gene family. Using the offspring of wild-caught mice, we examine individuality in the major urinary protein (MUP) scent marks at the DNA, RNA and protein levels. We show that individuality arises through a combination of variation at amino acid coding sites and differential transcription of central Mup genes across individuals, and we identify eSNPs in promoters. There is no evidence of post-transcriptional processes influencing phenotypic diversity as transcripts accurately predict the relative abundance of proteins in urine samples. The match between transcripts and urine samples taken six months earlier also emphasizes that the proportional relationships across central MUP isoforms in urine is stable. Balancing selection maintains coding variants at moderate frequencies, though pheromone diversity appears limited by interactions with vomeronasal receptors. We find that differential transcription of the central Mup paralogs within and between individuals significantly increases the individuality of pheromone blends. Balancing selection on gene regulation allows for increased individuality via combinatorial diversity in a limited number of pheromones. Individual recognition via scent is critical for many aspects of behavior including parental care, competition, cooperation and mate choice. While animal scents can differ in a huge number of dimensions, recent work has shown that only some specialized semiochemicals in scent marks are behaviorally relevant for individual recognition. How is individuality in specialized semiochemical blends produced and maintained in populations? At the extremes, individuality may depend on either a plethora of semiochemical isoforms or on combinatorial variation in a small number of shared isoforms across individuals. Analyzing the major urinary protein (MUP) pheromone blends of a wild population of house mice, we find evidence in favor of a combinatorial diversity model for the production and maintenance of individuality. Balancing selection maintains MUP proteins at moderate frequencies in the population, though interactions with the pheromone receptors appear to limit the extent of pheromone diversity in the system. By contrast, differential transcription of proteins greatly increases individuality in pheromone blends with balancing selection maintaining diversity in promoter regions associated with gene expression patterns. Selection maintaining combinatorial diversity in a limited set of behaviorally important semiochemicals may be a widespread mechanism generating and maintaining individuality in scent across taxa.
Collapse
|
48
|
Plasil M, Mohandesan E, Fitak RR, Musilova P, Kubickova S, Burger PA, Horin P. The major histocompatibility complex in Old World camelids and low polymorphism of its class II genes. BMC Genomics 2016; 17:167. [PMID: 26931144 PMCID: PMC4774177 DOI: 10.1186/s12864-016-2500-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 02/18/2016] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND The Major Histocompatibility Complex (MHC) is a genomic region containing genes with crucial roles in immune responses. MHC class I and class II genes encode antigen-presenting molecules expressed on the cell surface. To counteract the high variability of pathogens, the MHC evolved into a region of considerable heterogeneity in its organization, number and extent of polymorphism. Studies of MHCs in different model species contribute to our understanding of mechanisms of immunity, diseases and their evolution. Camels are economically important domestic animals and interesting biomodels. Three species of Old World camels have been recognized: the dromedary (Camelus dromedarius), Bactrian camel (Camelus bactrianus) and the wild camel (Camelus ferus). Despite their importance, little is known about the MHC genomic region, its organization and diversity in camels. The objectives of this study were to identify, map and characterize the MHC region of Old World camelids, with special attention to genetic variation at selected class MHC II loci. RESULTS Physical mapping located the MHC region to the chromosome 20 in Camelus dromedarius. Cytogenetic and comparative analyses of whole genome sequences showed that the order of the three major sub-regions is "Centromere - Class II - Class III - Class I". DRA, DRB, DQA and DQB exon 2 sequences encoding the antigen binding site of the corresponding class II antigen presenting molecules showed high degree of sequence similarity and extensive allele sharing across the three species. Unexpectedly low extent of polymorphism with low numbers of alleles and haplotypes was observed in all species, despite different geographic origins of the camels analyzed. The DRA locus was found to be polymorphic, with three alleles shared by all three species. DRA and DQA sequences retrieved from ancient DNA samples of Camelus dromedarius suggested that additional polymorphism might exist. CONCLUSIONS This study provided evidence that camels possess an MHC comparable to other mammalian species in terms of its genomic localization, organization and sequence similarity. We described ancient variation at the DRA locus, monomorphic in most species. The extent of molecular diversity of MHC class II genes seems to be substantially lower in Old World camels than in other mammalian species.
Collapse
Affiliation(s)
- Martin Plasil
- Department of Animal Genetics, Veterinary and Pharmaceutical University, Brno, Czech Republic.
- Ceitec VFU, RG Animal Immunogenomics, Brno, Czech Republic.
| | - Elmira Mohandesan
- Research Institute of Wildlife Ecology, Vetmeduni Vienna, Vienna, Austria.
- Institute of Population Genetics, Vetmeduni Vienna, Vienna, Austria.
| | - Robert R Fitak
- Institute of Population Genetics, Vetmeduni Vienna, Vienna, Austria.
- Department of Biology, Duke University, Durham, NC, USA.
| | - Petra Musilova
- Department of Genetics and Reproduction, Veterinary Research Institute, Brno, Czech Republic.
| | - Svatava Kubickova
- Department of Genetics and Reproduction, Veterinary Research Institute, Brno, Czech Republic.
| | - Pamela A Burger
- Research Institute of Wildlife Ecology, Vetmeduni Vienna, Vienna, Austria.
| | - Petr Horin
- Department of Animal Genetics, Veterinary and Pharmaceutical University, Brno, Czech Republic.
- Ceitec VFU, RG Animal Immunogenomics, Brno, Czech Republic.
| |
Collapse
|
49
|
Plönes T, Engel-Riedel W, Stoelben E, Limmroth C, Schildgen O, Schildgen V. Molecular Pathology and Personalized Medicine: The Dawn of a New Era in Companion Diagnostics-Practical Considerations about Companion Diagnostics for Non-Small-Cell-Lung-Cancer. J Pers Med 2016; 6:jpm6010003. [PMID: 26784235 PMCID: PMC4810382 DOI: 10.3390/jpm6010003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/12/2016] [Accepted: 01/13/2016] [Indexed: 01/04/2023] Open
Abstract
Companion diagnostics (CDx) have become a major tool in molecular pathology and assist in therapy decisions in an increasing number of various cancers. Particularly, the developments in lung cancer have been most impressing in the last decade and consequently lung cancer mutation testing and molecular profiling has become a major business of diagnostic laboratories. However, it has become difficult to decide which biomarkers are currently relevant for therapy decisions, as many of the new biomarkers are not yet approved as therapy targets, remain in the status of clinical studies, or still have not left the experimental phase. The current review is focussed on those markers that do have current therapy implications, practical implications arising from the respective companion diagnostics, and thus is focused on daily practice.
Collapse
Affiliation(s)
- Till Plönes
- Lungclinic Merheim, Department of Thoracic Surgery, Lung Clinic Cologne, Kliniken der Stadt Köln gGmbH, Cologne Merheim Hospital, Faculty of Health/School of Medicine, Witten/Herdecke, Ostmerheimerstrasse 200, 51109 Köln, Germany.
| | - Walburga Engel-Riedel
- Lungclinic Merheim, Department of Thoracic Surgery, Lung Clinic Cologne, Kliniken der Stadt Köln gGmbH, Cologne Merheim Hospital, Faculty of Health/School of Medicine, Witten/Herdecke, Ostmerheimerstrasse 200, 51109 Köln, Germany.
| | - Erich Stoelben
- Lungclinic Merheim, Department of Thoracic Surgery, Lung Clinic Cologne, Kliniken der Stadt Köln gGmbH, Cologne Merheim Hospital, Faculty of Health/School of Medicine, Witten/Herdecke, Ostmerheimerstrasse 200, 51109 Köln, Germany.
| | - Christina Limmroth
- Clinics for Internal Medicine Holweide, Hospital of Cologne, Neufelder Str. 34, 51067 Köln, Germany.
| | - Oliver Schildgen
- Institute for Pathology, Hospital of Cologne, Private University Witten/Herdecke, Ostmerheimerstrasse 200, 51109 Köln, Germany.
| | - Verena Schildgen
- Institute for Pathology, Hospital of Cologne, Private University Witten/Herdecke, Ostmerheimerstrasse 200, 51109 Köln, Germany.
| |
Collapse
|
50
|
Bateson ZW, Whittingham LA, Johnson JA, Dunn PO. Contrasting patterns of selection and drift between two categories of immune genes in prairie-chickens. Mol Ecol 2015; 24:6095-106. [PMID: 26547898 DOI: 10.1111/mec.13459] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 10/31/2015] [Accepted: 11/03/2015] [Indexed: 12/22/2022]
Abstract
Immune-receptor genes of the adaptive immune system, such as the major histocompatibility complex (MHC), are involved in recognizing specific pathogens and are known to have high rates of adaptive evolution, presumably as a consequence of rapid co-evolution between hosts and pathogens. In contrast, many 'mediating' genes of the immune system do not interact directly with specific pathogens and are involved in signalling (e.g. cytokines) or controlling immune cell growth. As a consequence, we might expect stronger selection at immune-receptor than mediating genes, but these two types of genes have not been compared directly in wild populations. Here, we tested the hypothesis that selection differs between MHC (class I and II) and mediating genes by comparing levels of population differentiation across the range of greater prairie-chickens (Tympanuchus cupido). As predicted, there was stronger population differentiation and isolation by distance at immune receptor (MHC) than at either mediating genes or neutral microsatellites, suggesting a stronger role of local adaptation at the MHC. In contrast, mediating genes displayed weaker differentiation between populations than neutral microsatellites, consistent with selection favouring similar alleles across populations for mediating genes. In addition to selection, drift also had a stronger effect on immune receptor (MHC) than mediating genes as indicated by the stronger decline of MHC variation in relation to population size. This is the first study in the wild to show that the effects of selection and drift on immune genes vary across populations depending on their functional role.
Collapse
Affiliation(s)
- Zachary W Bateson
- Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Linda A Whittingham
- Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Jeff A Johnson
- Department of Biological Sciences, Institute of Applied Sciences, University of North Texas, Denton, TX, USA
| | - Peter O Dunn
- Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| |
Collapse
|