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Vasoya D, Connelley T, Tzelos T, Todd H, Ballingall KT. Large scale transcriptional analysis of MHC class I haplotype diversity in sheep. HLA 2024; 103:e15356. [PMID: 38304958 DOI: 10.1111/tan.15356] [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: 10/25/2023] [Revised: 12/15/2023] [Accepted: 01/09/2024] [Indexed: 02/03/2024]
Abstract
Domestic sheep (Ovis aries) have been an important component of livestock agricultural production for thousands of years. Preserving genetic diversity within livestock populations maintains a capacity to respond to changing environments and rapidly evolving pathogens. MHC genetic diversity can influence immune functionality at individual and population levels. Here, we focus on defining functional MHC class I haplotype diversity in a large cohort of Scottish Blackface sheep pre-selected for high levels of MHC class II DRB1 diversity. Using high-throughput amplicon sequencing with three independent sets of barcoded primers we identified 134 MHC class I transcripts within 38 haplotypes. Haplotypes were identified with between two and six MHC class I genes, plus variable numbers of conserved sequences with very low read frequencies. One or two highly transcribed transcripts dominate each haplotype indicative of two highly polymorphic, classical MHC class I genes. Additional clusters of medium, low, and very low expressed transcripts are described, indicative of lower transcribed classical, non-classical and genes whose function remains to be determined.
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Affiliation(s)
- Deepali Vasoya
- Division of Infection and Immunity, The Roslin Institute, The University of Edinburgh, Scotland, UK
| | - Timothy Connelley
- Division of Infection and Immunity, The Roslin Institute, The University of Edinburgh, Scotland, UK
| | - Thomas Tzelos
- Division of Infection and Immunity, The Roslin Institute, The University of Edinburgh, Scotland, UK
- Moredun Research Institute, Pentlands Science Park, Scotland, UK
| | - Helen Todd
- Moredun Research Institute, Pentlands Science Park, Scotland, UK
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Gowane GR, Sharma P, Kumar R, Misra SS, Alex R, Vohra V, Chhotaray S, Sharma N, Chopra A, Kandalkar Y, Choudhary A, Magotra A. Population-wide genetic analysis of Ovar-DQA1 and DQA2 loci across sheep breeds in India revealed their evolutionary importance and fitness of sheep in a tropical climate. Anim Biotechnol 2023; 34:4645-4657. [PMID: 36847639 DOI: 10.1080/10495398.2023.2180010] [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: 03/01/2023]
Abstract
Genetic variability at the major histocompatibility complex (MHC) is important in any species due to significant role played by MHC for antigen presentation. DQA locus has not been studied for its genetic variability across sheep population in India. In the present study, MHC of sheep at DQA1 and DQA2 loci were evaluated across 17 Indian sheep breeds. Results revealed high degree of heterozygosity (10.34% to 100% for DQA1 and 37.39 to 100% for DQA2). 18 DQA1 alleles and 22 DQA2 alleles were isolated in different breeds. Nucleotide content for DQA region revealed richness of AT content (54.85% for DQA1 and 53.89% for DQA2). DQA1 and DQA2 sequences clustered independently. We could see evidence of divergence of DQA as DQA1 and DQA2 across sheep breeds. Wu-Kabat variability index revealed vast genetic variation across DQA1 and DQA2, specifically at peptide binding sites (PBS) that consisted 21 residues for DQA1 and 17 residues for DQA2. Evolutionary analysis revealed the presence of positive and balancing selection for DQA1 locus, however DQA2 was under purifying selection across sheep breeds. Higher heterozygosity and large diversity at both loci especially at PBS indicated the fitness of the sheep population for evading pathogens and adapt to the harsh tropical climate.
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Affiliation(s)
- G R Gowane
- Animal Genetics and Breeding Division, ICAR-National Dairy Research Institute, Karnal, India
| | - Priya Sharma
- Animal Genetics and Breeding Division, ICAR-National Dairy Research Institute, Karnal, India
| | - Rajiv Kumar
- Animal Genetics and Breeding Division, ICAR-Central Sheep and Wool Research Institute, Avikanagar
| | - S S Misra
- Animal Genetics and Breeding Division, ICAR-Central Sheep and Wool Research Institute, Avikanagar
| | - Rani Alex
- Animal Genetics and Breeding Division, ICAR-National Dairy Research Institute, Karnal, India
| | - V Vohra
- Animal Genetics and Breeding Division, ICAR-National Dairy Research Institute, Karnal, India
| | - S Chhotaray
- Animal Genetics and Breeding Division, ICAR-National Dairy Research Institute, Karnal, India
| | - Nikita Sharma
- Animal Health Section, ICAR-Central Institute for Research on Goats, Makhdoom, India
| | - Ashish Chopra
- Animal Genetics and Breeding Division, ICAR-Arid Region Campus, Central Sheep and Wool Research Institute, Bikaner, India
| | - Yogesh Kandalkar
- Deccani Sheep Breeding Unit, NWPSI at Mahatma Phule Krishi Vidyapith, Rahuri, India
| | | | - Ankit Magotra
- Animal Genetics and Breeding Division, Chaudhary Charan Singh Haryana Agricultural University, Hisar, India
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Ren Y, MacPhillamy C, To TH, Smith TPL, Williams JL, Low WY. Adaptive selection signatures in river buffalo with emphasis on immune and major histocompatibility complex genes. Genomics 2021; 113:3599-3609. [PMID: 34455036 DOI: 10.1016/j.ygeno.2021.08.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 08/11/2021] [Accepted: 08/23/2021] [Indexed: 11/27/2022]
Abstract
River buffalo is an agriculturally important species with many traits, such as disease tolerance, which promote its use worldwide. Highly contiguous genome assemblies of the river buffalo, goat, pig, human and two cattle subspecies were aligned to study gene gains and losses and signs of positive selection. The gene families that have changed significantly in river buffalo since divergence from cattle play important roles in protein degradation, the olfactory receptor system, detoxification and the immune system. We used the branch site model in PAML to analyse single-copy orthologs to identify positively selected genes that may be involved in skin differentiation, mammary development and bone formation in the river buffalo branch. The high contiguity of the genomes enabled evaluation of differences among species in the major histocompatibility complex. We identified a Babesia-like L1 LINE insertion in the DRB1-like gene in the river buffalo and discuss the implication of this finding.
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Affiliation(s)
- Yan Ren
- The Davies Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Callum MacPhillamy
- The Davies Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA 5371, Australia
| | - Thu-Hien To
- Norwegian University of Life Sciences: NMBU, Universitetstunet 3, 1430 Ås, Norway
| | | | - John L Williams
- The Davies Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA 5371, Australia; Dipartimento di Scienze Animali, della Nutrizione e degli Alimenti, Università Cattolica del Sacro Cuore, Piacenza, Italy
| | - Wai Yee Low
- The Davies Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, SA 5371, Australia.
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Dicks KL, Pemberton JM, Ballingall KT. Characterisation of major histocompatibility complex class IIa haplotypes in an island sheep population. Immunogenetics 2019; 71:383-393. [PMID: 30796497 PMCID: PMC6525122 DOI: 10.1007/s00251-019-01109-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 02/08/2019] [Indexed: 12/11/2022]
Abstract
The ovine MHC class IIa is known to consist of six to eight loci located in close proximity on chromosome 20, forming haplotypes that are typically inherited without recombination. Here, we characterise the class IIa haplotypes within the Soay sheep (Ovis aries) on St. Kilda to assess the diversity present within this unmanaged island population. We used a stepwise sequence-based genotyping strategy to identify alleles at seven polymorphic MHC class IIa loci in a sample of 118 Soay sheep from four cohorts spanning 15 years of the long-term study on St. Kilda. DRB1, the most polymorphic MHC class II locus, was characterised first in all 118 sheep and identified six alleles. Using DRB1 homozygous animals, the DQA (DQA1, DQA2 and DQA2-like) and DQB (DQB1, DQB2 and DQB2-like) loci were sequenced, revealing eight haplotypes. Both DQ1/DQ2 and DQ2/DQ2-like haplotype configurations were identified and a single haplotype carrying three DQB alleles. A test sample of 94 further individuals typed at the DRB1 and DQA loci found no exceptions to the eight identified haplotypes and a haplotype homozygosity of 21.3%. We found evidence of historic positive selection at DRB1, DQA and DQB. The limited variation at MHC class IIa loci in Soay sheep enabled haplotype characterisation but showed that no single locus could capture the full extent of the expressed variation in the region.
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Affiliation(s)
- Kara L Dicks
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK.
| | - Josephine M Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Keith T Ballingall
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Penicuik, Midlothian, EH26 OPZ, UK
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