Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California.
The genes of the Major Histocompatibility Complex (MHC) play an important role in the vertebrate immune response and are among the most polymorphic genes known in vertebrates. In some marine mammals, MHC genes have been shown to be characterized by low levels of polymorphism compared to terrestrial...
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ftcdlib:oai:escholarship.org:ark:/13030/qt38d9t8kb 2023-06-11T04:10:27+02:00 Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California. Moreno-Santillán, Diana D Lacey, Eileen A Gendron, Diane Ortega, Jorge Chiang, Tzen-Yuh e0141296 2016-01-01 application/pdf https://escholarship.org/uc/item/38d9t8kb unknown eScholarship, University of California qt38d9t8kb https://escholarship.org/uc/item/38d9t8kb public PloS one, vol 11, iss 1 Animals Histocompatibility Antigens Class II Likelihood Functions Sequence Alignment Phylogeny Amino Acid Sequence Base Sequence Gene Frequency Haplotypes Alleles Exons Molecular Sequence Data California Balaenoptera Genetic Variation Selection Genetic Genetic Loci HLA-DQ beta-Chains Genetics General Science & Technology article 2016 ftcdlib 2023-05-08T17:56:45Z The genes of the Major Histocompatibility Complex (MHC) play an important role in the vertebrate immune response and are among the most polymorphic genes known in vertebrates. In some marine mammals, MHC genes have been shown to be characterized by low levels of polymorphism compared to terrestrial taxa; this reduction in variation is often explained as a result of lower pathogen pressures in marine habitats. To determine if this same reduction in variation applies to the migratory population of blue whales (Balaenoptera musculus) that occurs in the Gulf of California, we genotyped a 172 bp fragment of exon 2 of the MHC Class II DQB locus for 80 members of this population. Twenty-two putatively functional DQB allotypes were identified, all of which were homologous with DQB sequences from other cetacean species. Up to 5 putative alleles per individual were identified, suggesting that gene duplication has occurred at this locus. Rates of non-synonymous to synonymous substitutions (ω) and maximum likelihood analyses of models of nucleotide variation provided potential evidence of ongoing positive selection at this exon. Phylogenetic analyses of DQB alleles from B. musculus and 16 other species of cetaceans revealed trans-specific conservation of MHC variants, suggesting that selection has acted on this locus over prolonged periods of time. Collectively our findings reveal that immunogenic variation in blue whales is comparable to that in terrestrial mammals, thereby providing no evidence that marine taxa are subject to reduced pathogen-induced selective pressures. Article in Journal/Newspaper Balaenoptera musculus Blue whale University of California: eScholarship |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Animals Histocompatibility Antigens Class II Likelihood Functions Sequence Alignment Phylogeny Amino Acid Sequence Base Sequence Gene Frequency Haplotypes Alleles Exons Molecular Sequence Data California Balaenoptera Genetic Variation Selection Genetic Genetic Loci HLA-DQ beta-Chains Genetics General Science & Technology |
spellingShingle |
Animals Histocompatibility Antigens Class II Likelihood Functions Sequence Alignment Phylogeny Amino Acid Sequence Base Sequence Gene Frequency Haplotypes Alleles Exons Molecular Sequence Data California Balaenoptera Genetic Variation Selection Genetic Genetic Loci HLA-DQ beta-Chains Genetics General Science & Technology Moreno-Santillán, Diana D Lacey, Eileen A Gendron, Diane Ortega, Jorge Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California. |
topic_facet |
Animals Histocompatibility Antigens Class II Likelihood Functions Sequence Alignment Phylogeny Amino Acid Sequence Base Sequence Gene Frequency Haplotypes Alleles Exons Molecular Sequence Data California Balaenoptera Genetic Variation Selection Genetic Genetic Loci HLA-DQ beta-Chains Genetics General Science & Technology |
description |
The genes of the Major Histocompatibility Complex (MHC) play an important role in the vertebrate immune response and are among the most polymorphic genes known in vertebrates. In some marine mammals, MHC genes have been shown to be characterized by low levels of polymorphism compared to terrestrial taxa; this reduction in variation is often explained as a result of lower pathogen pressures in marine habitats. To determine if this same reduction in variation applies to the migratory population of blue whales (Balaenoptera musculus) that occurs in the Gulf of California, we genotyped a 172 bp fragment of exon 2 of the MHC Class II DQB locus for 80 members of this population. Twenty-two putatively functional DQB allotypes were identified, all of which were homologous with DQB sequences from other cetacean species. Up to 5 putative alleles per individual were identified, suggesting that gene duplication has occurred at this locus. Rates of non-synonymous to synonymous substitutions (ω) and maximum likelihood analyses of models of nucleotide variation provided potential evidence of ongoing positive selection at this exon. Phylogenetic analyses of DQB alleles from B. musculus and 16 other species of cetaceans revealed trans-specific conservation of MHC variants, suggesting that selection has acted on this locus over prolonged periods of time. Collectively our findings reveal that immunogenic variation in blue whales is comparable to that in terrestrial mammals, thereby providing no evidence that marine taxa are subject to reduced pathogen-induced selective pressures. |
author2 |
Chiang, Tzen-Yuh |
format |
Article in Journal/Newspaper |
author |
Moreno-Santillán, Diana D Lacey, Eileen A Gendron, Diane Ortega, Jorge |
author_facet |
Moreno-Santillán, Diana D Lacey, Eileen A Gendron, Diane Ortega, Jorge |
author_sort |
Moreno-Santillán, Diana D |
title |
Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California. |
title_short |
Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California. |
title_full |
Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California. |
title_fullStr |
Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California. |
title_full_unstemmed |
Genetic Variation at Exon 2 of the MHC Class II DQB Locus in Blue Whale (Balaenoptera musculus) from the Gulf of California. |
title_sort |
genetic variation at exon 2 of the mhc class ii dqb locus in blue whale (balaenoptera musculus) from the gulf of california. |
publisher |
eScholarship, University of California |
publishDate |
2016 |
url |
https://escholarship.org/uc/item/38d9t8kb |
op_coverage |
e0141296 |
genre |
Balaenoptera musculus Blue whale |
genre_facet |
Balaenoptera musculus Blue whale |
op_source |
PloS one, vol 11, iss 1 |
op_relation |
qt38d9t8kb https://escholarship.org/uc/item/38d9t8kb |
op_rights |
public |
_version_ |
1768384849269227520 |