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Matthews AE, Boves TJ, Percy KL, Schelsky WM, Wijeratne AJ. Population Genomics of Pooled Samples: Unveiling Symbiont Infrapopulation Diversity and Host-Symbiont Coevolution. Life (Basel) 2023; 13:2054. [PMID: 37895435 PMCID: PMC10608719 DOI: 10.3390/life13102054] [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: 06/29/2023] [Revised: 09/30/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Microscopic symbionts represent crucial links in biological communities. However, they present technical challenges in high-throughput sequencing (HTS) studies due to their small size and minimal high-quality DNA yields, hindering our understanding of host-symbiont coevolution at microevolutionary and macroevolutionary scales. One approach to overcome those barriers is to pool multiple individuals from the same infrapopulation (i.e., individual host) and sequence them together (Pool-Seq), but individual-level information is then compromised. To simultaneously address both issues (i.e., minimal DNA yields and loss of individual-level information), we implemented a strategic Pool-Seq approach to assess variation in sequencing performance and categorize genetic diversity (single nucleotide polymorphisms (SNPs)) at both the individual-level and infrapopulation-level for microscopic feather mites. To do so, we collected feathers harboring mites (Proctophyllodidae: Amerodectes protonotaria) from four individual Prothonotary Warblers (Parulidae: Protonotaria citrea). From each of the four hosts (i.e., four mite infrapopulations), we conducted whole-genome sequencing on three extraction pools consisting of different numbers of mites (1 mite, 5 mites, and 20 mites). We found that samples containing pools of multiple mites had more sequencing reads map to the feather mite reference genome than did the samples containing only a single mite. Mite infrapopulations were primarily genetically structured by their associated individual hosts (not pool size) and the majority of SNPs were shared by all pools within an infrapopulation. Together, these results suggest that the patterns observed are driven by evolutionary processes occurring at the infrapopulation level and are not technical signals due to pool size. In total, despite the challenges presented by microscopic symbionts in HTS studies, this work highlights the value of both individual-level and infrapopulation-level sequencing toward our understanding of host-symbiont coevolution at multiple evolutionary scales.
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Affiliation(s)
- Alix E. Matthews
- College of Sciences and Mathematics and Molecular Biosciences Program, Arkansas State University, Jonesboro, AR 72401, USA
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA; (T.J.B.); (A.J.W.)
| | - Than J. Boves
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA; (T.J.B.); (A.J.W.)
| | - Katie L. Percy
- Audubon Delta, National Audubon Society, Baton Rouge, LA 70808, USA;
- United States Department of Agriculture, Natural Resources Conservation Service, Addis, LA 70710, USA
| | - Wendy M. Schelsky
- Department of Evolution, Ecology, and Behavior, School of Integrative Biology, University of Illinois, Urbana-Champaign, Champaign, IL 61801, USA;
- Prairie Research Institute, Illinois Natural History Survey, University of Illinois, Urbana-Champaign, Champaign, IL 61820, USA
| | - Asela J. Wijeratne
- Department of Biological Sciences, Arkansas State University, Jonesboro, AR 72401, USA; (T.J.B.); (A.J.W.)
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Sromek L, Ylinen E, Kunnasranta M, Maduna SN, Sinisalo T, Michell CT, Kovacs KM, Lydersen C, Ieshko E, Andrievskaya E, Alexeev V, Leidenberger S, Hagen SB, Nyman T. Loss of species and genetic diversity during colonization: Insights from acanthocephalan parasites in northern European seals. Ecol Evol 2023; 13:e10608. [PMID: 37869427 PMCID: PMC10585441 DOI: 10.1002/ece3.10608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/24/2023] Open
Abstract
Studies on host-parasite systems that have experienced distributional shifts, range fragmentation, and population declines in the past can provide information regarding how parasite community richness and genetic diversity will change as a result of anthropogenic environmental changes in the future. Here, we studied how sequential postglacial colonization, shifts in habitat, and reduced host population sizes have influenced species richness and genetic diversity of Corynosoma (Acanthocephala: Polymorphidae) parasites in northern European marine, brackish, and freshwater seal populations. We collected Corynosoma population samples from Arctic, Baltic, Ladoga, and Saimaa ringed seal subspecies and Baltic gray seals, and then applied COI barcoding and triple-enzyme restriction-site associated DNA (3RAD) sequencing to delimit species, clarify their distributions and community structures, and elucidate patterns of intraspecific gene flow and genetic diversity. Our results showed that Corynosoma species diversity reflected host colonization histories and population sizes, with four species being present in the Arctic, three in the Baltic Sea, two in Lake Ladoga, and only one in Lake Saimaa. We found statistically significant population-genetic differentiation within all three Corynosoma species that occur in more than one seal (sub)species. Genetic diversity tended to be high in Corynosoma populations originating from Arctic ringed seals and low in the landlocked populations. Our results indicate that acanthocephalan communities in landlocked seal populations are impoverished with respect to both species and intraspecific genetic diversity. Interestingly, the loss of genetic diversity within Corynosoma species seems to have been less drastic than in their seal hosts, possibly due to their large local effective population sizes resulting from high infection intensities and effective intra-host population mixing. Our study highlights the utility of genomic methods in investigations of community composition and genetic diversity of understudied parasites.
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Affiliation(s)
- Ludmila Sromek
- Department of Marine Ecosystems Functioning, Institute of OceanographyUniversity of GdanskGdyniaPoland
| | - Eeva Ylinen
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandJoensuuFinland
| | - Mervi Kunnasranta
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandJoensuuFinland
- Natural Resources Institute FinlandJoensuuFinland
| | - Simo N. Maduna
- Department of Ecosystem in the Barents RegionNorwegian Institute of Bioeconomy ResearchSvanvikNorway
| | - Tuula Sinisalo
- Department of Biological and Environmental SciencesUniversity of JyväskyläJyväskyläFinland
| | - Craig T. Michell
- Department of Environmental and Biological SciencesUniversity of Eastern FinlandJoensuuFinland
- Red Sea Research CenterKing Abdullah University of Science and TechnologyJeddahSaudi Arabia
| | | | | | - Evgeny Ieshko
- Institute of Biology, Karelian Research CentreRussian Academy of SciencesPetrozavodskRussia
| | | | | | - Sonja Leidenberger
- Department of Biology and Bioinformatics, School of BioscienceUniversity of SkövdeSkövdeSweden
| | - Snorre B. Hagen
- Department of Ecosystem in the Barents RegionNorwegian Institute of Bioeconomy ResearchSvanvikNorway
| | - Tommi Nyman
- Department of Ecosystem in the Barents RegionNorwegian Institute of Bioeconomy ResearchSvanvikNorway
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Techer MA, Roberts JMK, Cartwright RA, Mikheyev AS. The first steps toward a global pandemic: Reconstructing the demographic history of parasite host switches in its native range. Mol Ecol 2022; 31:1358-1374. [PMID: 34882860 PMCID: PMC11105409 DOI: 10.1111/mec.16322] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/23/2021] [Accepted: 11/29/2021] [Indexed: 12/14/2022]
Abstract
Host switching allows parasites to expand their niches. However, successful switching may require suites of adaptations and also may decrease performance on the old host. As a result, reductions in gene flow accompany many host switches, driving speciation. Because host switches tend to be rapid, it is difficult to study them in real-time, and their demographic parameters remain poorly understood. As a result, fundamental factors that control subsequent parasite evolution, such as the size of the switching population or the extent of immigration from the original host, remain largely unknown. To shed light on the host switching process, we explored how host switches occur in independent host shifts by two ectoparasitic honey bee mites (Varroa destructor and V. jacobsoni). Both switched to the western honey bee (Apis mellifera) after being brought into contact with their ancestral host (Apis cerana), ~70 and ~12 years ago, respectively. Varroa destructor subsequently caused worldwide collapses of honey bee populations. Using whole-genome sequencing on 63 mites collected in their native ranges from both the ancestral and novel hosts, we were able to reconstruct the known temporal dynamics of the switch. We further found multiple previously undiscovered mitochondrial lineages on the novel host, along with the genetic equivalent of tens of individuals that were involved in the initial host switch. Despite being greatly reduced, some gene flow remains between mites adapted to different hosts. Our findings suggest that while reproductive isolation may facilitate the fixation of traits beneficial for exploiting the new host, ongoing genetic exchange may allow genetic amelioration of inbreeding effects.
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Affiliation(s)
- Maeva A Techer
- Okinawa Institute of Science and Technology, Okinawa, Japan
| | - John M K Roberts
- Commonwealth Scientific & Industrial Research Organisation, Canberra, Australian Capital Territory, Australia
| | - Reed A Cartwright
- The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
- School of Life Sciences, Arizona State University, Tempe, Arizona, USA
| | - Alexander S Mikheyev
- Okinawa Institute of Science and Technology, Okinawa, Japan
- Australian National University, Canberra, Australian Capital Territory, Australia
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Zhang R, Guo Z, Fang L, Zhong C, Duke NC, Shi S. Population subdivision promoted by a sea-level-change-driven bottleneck: A glimpse from the evolutionary history of the mangrove plant Aegiceras corniculatum. Mol Ecol 2021; 31:780-797. [PMID: 34826188 DOI: 10.1111/mec.16290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 11/09/2021] [Accepted: 11/15/2021] [Indexed: 11/30/2022]
Abstract
Historic climate changes drive geographical populations of coastal plants to contract and recover dynamically, even die out completely. Species suffering from such bottlenecks usually lose intraspecific genetic diversity, but how do these events influence population subdivision patterns of coastal plants? Here, we investigated this question in the typical coastal plant: mangrove species Aegiceras corniculatum. Inhabiting the intertidal zone of the tropical and subtropical coast of the Indo-West Pacific oceans, its populations are deemed to be greatly shaped by historic sea-level fluctuations. Using dual methods of Sanger and Illumina sequencing, we found that the 18 sampled populations were structured into two groups, namely, the "Indo-Malayan" group, comprising three subgroups (the northern South China Sea, Gulf of Bengal, and Bali), and the "Pan-Australasia" group, comprising the subgroups of the southern South China Sea and Australasia. Based on the approximate Bayesian computations and Stairway Plot, we inferred that the southern South China Sea subgroup, which penetrates the interior of the "Indo-Malayan" group, originated from the Australasia subgroup, accompanied by a severe bottleneck event, with a spot of gene flow from both the Australasia and "Indo-Malayan" groups. Geographical barriers such as the Sundaland underlie the genetic break between Indian and Pacific Oceans, but the discontinuity between southern and northern South China Sea was originated from genetic drift in the bottleneck event. Hence, we revealed a case evidencing that the bottleneck event promoted population subdivision. This conclusion may be applicable in other taxa beyond coastal plants.
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Affiliation(s)
- Rufan Zhang
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, China
| | - Zixiao Guo
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, China
| | - Lu Fang
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, China.,Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, South China Normal University, Guangzhou, China
| | - Cairong Zhong
- Hainan Academy of Forestry (Hainan Academy of Mangrove), Haikou, China
| | - Norman C Duke
- Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, Australia
| | - Suhua Shi
- State Key Laboratory of Biocontrol, Guangdong Key Laboratory of Plant Resources, School of Life Sciences, Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Sun Yat-sen University, Guangzhou, China
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Tepolt CK, Grosholz ED, de Rivera CE, Ruiz GM. Balanced polymorphism fuels rapid selection in an invasive crab despite high gene flow and low genetic diversity. Mol Ecol 2021; 31:55-69. [PMID: 34431151 DOI: 10.1111/mec.16143] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 05/24/2021] [Accepted: 08/13/2021] [Indexed: 12/30/2022]
Abstract
Adaptation across environmental gradients has been demonstrated in numerous systems with extensive dispersal, despite high gene flow and consequently low genetic structure. The speed and mechanisms by which such adaptation occurs remain poorly resolved, but are critical to understanding species spread and persistence in a changing world. Here, we investigate these mechanisms in the European green crab Carcinus maenas, a globally distributed invader. We focus on a northwestern Pacific population that spread across >12 degrees of latitude in 10 years from a single source, following its introduction <35 years ago. Using six locations spanning >1500 km, we examine genetic structure using 9376 single nucleotide polymorphisms (SNPs). We find high connectivity among five locations, with significant structure between these locations and an enclosed lagoon with limited connectivity to the coast. Among the five highly connected locations, the only structure observed was a cline driven by a handful of SNPs strongly associated with latitude and winter temperature. These SNPs are almost exclusively found in a large cluster of genes in strong linkage disequilibrium that was previously identified as a candidate for cold tolerance adaptation in this species. This region may represent a balanced polymorphism that evolved to promote rapid adaptation in variable environments despite high gene flow, and which now contributes to successful invasion and spread in a novel environment. This research suggests an answer to the paradox of genetically depauperate yet successful invaders: populations may be able to adapt via a few variants of large effect despite low overall diversity.
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Affiliation(s)
- Carolyn K Tepolt
- Department of Biology, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
| | - Edwin D Grosholz
- Department of Environmental Science and Policy, University of California, Davis, California, USA
| | - Catherine E de Rivera
- Department of Environmental Science and Management, Portland State University, Portland, Oregon, USA
| | - Gregory M Ruiz
- Smithsonian Environmental Research Center, Smithsonian Institution, Edgewater, Maryland, USA
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Spradling TA, Place AC, Campbell AL, Demastes JW. Mitochondrial genome of Geomydoecus aurei, a pocket-gopher louse. PLoS One 2021; 16:e0254138. [PMID: 34314423 PMCID: PMC8315533 DOI: 10.1371/journal.pone.0254138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 06/18/2021] [Indexed: 11/28/2022] Open
Abstract
Parasitic lice demonstrate an unusual array of mitochondrial genome architectures and gene arrangements. We characterized the mitochondrial genome of Geomydoecus aurei, a chewing louse (Phthiraptera: Trichodectidae) found on pocket gophers (Rodentia: Geomyidae) using reads from both Illumina and Oxford Nanopore sequencing coupled with PCR, cloning, and Sanger sequencing to verify structure and arrangement for each chromosome. The genome consisted of 12 circular mitochondrial chromosomes ranging in size from 1,318 to 2,088 nucleotides (nt). Total genome size was 19,015 nt. All 37 genes typical of metazoans (2 rRNA genes, 22 tRNA genes, and 13 protein-coding genes) were present. An average of 26% of each chromosome was composed of non-gene sequences. Within the non-gene region of each chromosome, there was a 79-nt nucleotide sequence that was identical among chromosomes and a conserved sequence with secondary structure that was always followed by a poly-T region. We hypothesize that these regions may be important in the initiation of transcription and DNA replication, respectively. The G. aurei genome shares 8 derived gene clusters with other chewing lice of mammals, but in G. aurei, genes on several chromosomes are not contiguous.
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Affiliation(s)
- Theresa A. Spradling
- Department of Biology, University of Northern Iowa, Cedar Falls, Iowa, United States of America
| | - Alexandra C. Place
- Department of Biology, University of Northern Iowa, Cedar Falls, Iowa, United States of America
| | - Ashley L. Campbell
- Department of Biology, University of Northern Iowa, Cedar Falls, Iowa, United States of America
| | - James W. Demastes
- Department of Biology, University of Northern Iowa, Cedar Falls, Iowa, United States of America
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Mauldin MR, Haynie ML, Vrla SC, Bradley RD. Temporal evaluation of a woodrat (genus Neotoma) hybrid zone based on genotypic and georeferenced data. J Mammal 2021. [DOI: 10.1093/jmammal/gyaa164] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Mauldin et al. (2014) examined 103 woodrats collected in 1988 from a putative contact zone located in Major County, Oklahoma, and provided evidence for a substantial level of hybridization between Neotoma floridana and N. micropus. This site was resampled in 2010, with 42 woodrats collected, and again in 2011, when an additional 88 woodrats were collected from 11 localities along a transect extending northwest to southeast of the center of the hybrid zone. These specimens were examined to: 1) serve as independent data sets, separated by 22 years, for a temporal comparison of hybrid zone characteristics and 2) determine the geographic extent of genetic introgression between the two species. All individuals were genotyped at 11 genetic markers (eight microsatellite loci, one mitochondrial gene—Cytochrome b, and two nuclear introns—intron 2 of the vertebrate alcohol dehydrogenase gene and intron 7 of the beta-fibrinogen gene) that were shown to be informative in the original study. Levels of allelic introgression were assessed at 12 localities (11 new localities, as well as the previously sampled putative contact zone) to determine size and continuity of the hybrid zone. Expanded geographic sampling revealed evidence of genetic introgression at 11 of 12 localities, although only two localities were determined to be active areas of hybridization in 2011. The temporal comparison revealed that characteristics of the hybrid zone (i.e., frequency of hybridization, directionality, location of the zone, and ratios of hybrid classes) remained similar between sampling events. These findings suggest hybridization between these species is ongoing but is intermittent and potentially ephemeral in this region.
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Affiliation(s)
- Matthew R Mauldin
- Department of Biological Sciences, Texas Tech University, Lubbock, TX-3131, USA
| | - Michelle L Haynie
- Department of Biology, University of Central Oklahoma, Edmond, OK, USA
| | - Sarah C Vrla
- Department of Biological Sciences, Texas Tech University, Lubbock, TX-3131, USA
| | - Robert D Bradley
- Department of Biological Sciences, Texas Tech University, Lubbock, TX-3131, USA
- The Museum of Texas Tech University, Lubbock, TX, USA
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