MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

颯田, 葉子; YASUKOCHI, Yoshiki; KUROSAKI, Toshifumi; YONEDA, Masaaki; KOIKE, Hiroko; SATTA, Yoko

doi:https://doi.org/10.1186/1471-2148-12-230

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MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

https://ir.soken.ac.jp/records/3321

名前 / ファイル	ライセンス	アクション
1471-2148-12-230 (7.8 MB)

Item type

学術雑誌論文 / Journal Article(1)

公開日

2013-01-17

タイトル

MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

タイトル

MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

言語

eng

資源タイプ

資源タイプ識別子

http://purl.org/coar/resource_type/c_6501

資源タイプ

journal article

著者

YASUKOCHI, Yoshiki
KUROSAKI, Toshifumi
YONEDA, Masaaki
KOIKE, Hiroko
SATTA, Yoko

著者別名

颯田, 葉子

抄録

内容記述タイプ

Abstract

内容記述

Background
The major histocompatibility complex (MHC) genes are one of the most important genetic systems in the vertebrate immune response. The diversity of MHC genes may directly influence the survival of individuals against infectious disease. However, there has been no investigation of MHC diversity in the Asiatic black bear (Ursus thibetanus). Here, we analyzed 270-bp nucleotide sequences of the entire exon 2 region of the MHC DQB gene by using 188 samples from the Japanese black bear (Ursus thibetanus japonicus) from 12 local populations.
Results
Among 185 of 188 samples, we identified 44 MHC variants that encoded 31 different amino acid sequences (allotypes) and one putative. The phylogenetic analysis suggests that MHC variants detected from the Japanese black bear are derived from the DQB locus. One of the 31 DQB allotypes, Urth-DQB*01, was found to be common to all local populations. Moreover, this allotype was shared between the black bear on the Asian continent and the Japanese black bear, suggesting that Urth-DQB*01 might have been maintained in the ancestral black bear population for at least 300,000 years. Our findings, from calculating the ratio of non-synonymous to synonymous substitutions, indicate that balancing selection has maintained genetic variation of peptide-binding residues at the DQB locus of the Japanese black bear. From examination of genotype frequencies among local populations, we observed a considerably lower level of observed heterozygosity than expected.
Conclusions
The low level of observed heterozygosity suggests that genetic drift reduced DQB diversity in the Japanese black bear due to a bottleneck event at the population or species level. The decline of DQB diversity might have been accelerated by the loss of rare variants that have been maintained by negative frequency-dependent selection. Nevertheless, DQB diversity of the black bear appears to be relatively high compared with some other endangered mammalian species. This result suggests that the Japanese black bears may also retain more potential resistance against pathogens than other endangered mammalian species. To prevent further decline of potential resistance against pathogens, a conservation policy for the Japanese black bear should be designed to maintain MHC rare variants in each local population.

書誌情報

BMC Evolutionary Biology
en : BMC Evolutionary Biology

p. 230, 発行日 2012-11-29

出版者

BioMed Central

ISSN

収録物識別子タイプ

ISSN

収録物識別子

14712148

DOI

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Ver.1

2023-06-20 14:11:36.511072

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MHC class II DQB diversity in the Japanese black bear, Ursus thibetanus japonicus

× YASUKOCHI, Yoshiki

× KUROSAKI, Toshifumi

× YONEDA, Masaaki

× KOIKE, Hiroko

× SATTA, Yoko

× 颯田, 葉子

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