Evolution of major histocompatibility complex class I and class II genes in the brown bear.
Evolution of major histocompatibility complex class I and class II genes in the brown bear.
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DOI：
10.1186/1471-2148-12-197
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发表时间：
2012-10-02
影响因子：
3.4
通讯作者：
Radwan J
中科院分区：
文献类型：
--
作者：
Kuduk K;Babik W;Bojarska K;Sliwińska EB;Kindberg J;Taberlet P;Swenson JE;Radwan J
主要组织相容性复合体（MHC）蛋白是脊椎动物免疫应答的重要组成部分，由脊椎动物中最具多态性的基因编码。在这里，我们调查的序列变异和进化的MHC I类和II类DRB，DQA和DQB基因在棕熊熊的多态性水平，估计正选择作用于他们的强度，并评估的程度，基因的同源性和跨物种多态性在熊科。共检测到37个MHC Ⅰ类、16个MHC Ⅱ类DRB、4个DQB和2个DQA等位基因。我们证实了几个位点的表达：三个MHC I类，两个DRB，两个DQB和一个DQA。MHC I类还含有两个簇的非表达序列。斯堪的纳维亚棕熊的北方和南方种群之间的MHC I类和DRB等位基因频率不同。在DRB和DQB基因座的推定抗原结合位点，非同义置换率（dN）超过同义置换率（dS），在MHC I类基因座略显着。密码子进化模型支持DRB和MHC I类基因座的正选择。MHC I类和MHC II类序列均与大熊猫的基因簇具有同源性。历史正向选择作用于MHC I类、II类DRB和DQB，但不作用于DQA基因座。DRB基因座上的历史正选择信号特别强，这可能是犬科动物的一个普遍特征。MHC I类假基因的存在可能表明该类基因在出生和死亡过程中的周转更快。在MHC基因座的南北人口结构可能反映了人口的起源从单独的冰川避难所。
Major histocompatibility complex (MHC) proteins constitute an essential component of the vertebrate immune response, and are coded by the most polymorphic of the vertebrate genes. Here, we investigated sequence variation and evolution of MHC class I and class II DRB, DQA and DQB genes in the brown bear Ursus arctos to characterise the level of polymorphism, estimate the strength of positive selection acting on them, and assess the extent of gene orthology and trans-species polymorphism in Ursidae. We found 37 MHC class I, 16 MHC class II DRB, four DQB and two DQA alleles. We confirmed the expression of several loci: three MHC class I, two DRB, two DQB and one DQA. MHC class I also contained two clusters of non-expressed sequences. MHC class I and DRB allele frequencies differed between northern and southern populations of the Scandinavian brown bear. The rate of nonsynonymous substitutions (dN) exceeded the rate of synonymous substitutions (dS) at putative antigen binding sites of DRB and DQB loci and, marginally significantly, at MHC class I loci. Models of codon evolution supported positive selection at DRB and MHC class I loci. Both MHC class I and MHC class II sequences showed orthology to gene clusters found in the giant panda Ailuropoda melanoleuca. Historical positive selection has acted on MHC class I, class II DRB and DQB, but not on the DQA locus. The signal of historical positive selection on the DRB locus was particularly strong, which may be a general feature of caniforms. The presence of MHC class I pseudogenes may indicate faster gene turnover in this class through the birth-and-death process. South–north population structure at MHC loci probably reflects origin of the populations from separate glacial refugia.
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影响因子：
3.9
作者：
Furlong, Rebecca F.;Yang, Ziheng
通讯作者：
Yang, Ziheng
DOI：
10.1002/jez.b.21327
发表时间：
2010-05-15
影响因子：
2.2
作者：
Chen, Yi-Yan;Zhang, Ying-Ying;Fang, Sheng-Guo
通讯作者：
Fang, Sheng-Guo
影响因子：
10.7
作者：
Froeschke, G;Sommer, S
通讯作者：
Sommer, S
影响因子：
4.9
作者：
Babik, W.;Pabijan, M.;Radwan, J.
通讯作者：
Radwan, J.
影响因子：
0.9
作者：
Goda, Naoki;Mano, Tsutomu;Masuda, Ryuichi
通讯作者：
Masuda, Ryuichi