扩大MHC-IIB已经限制了MHC-IIA在Passerines的演变
Iris Liesbeth Ruesink-Bueno1, Anna Drews1, Emily Amelia O'Connor1
1Department of Biology, Molecular Ecology and Evolution Lab, Lund University, Lund, Sweden.
Genome biology and evolution
|October 27, 2024
概括
通过者在MHC-IIA基因 (DAA1) 上表现出较弱的正选择和较强的负选择. 这种进化约束与MHC-IIB基因 (DAB1) 的扩张有关,而不是另一个MHC位点的损失.
科学领域:
- 免疫遗传学 免疫遗传学
- 进化生物学 进化生物学
- 鸟类基因组学 鸟类基因组学
背景情况:
- 主性基因相容性复合体 (MHC) 对于适应性免疫至关重要,它编码出抗原的分子.
- 鸟类MHCII类 (MHC-II) 基因存在于两个位置 (DA1,DA2) 与A基因 (DAA) 和B基因 (DAB).
- 通过者已经失去了DA2位点,并修改了DA1位点结构.
研究的目的:
- 为了研究鸟中DAA1基因的进化压力.
- 为了比较鸟和非鸟之间DAA1的选择模式.
- 确定影响鸟DAA1演变的因素.
主要方法:
- 在15种类动物中对DAA1基因进行基因定型.
- 在鸟和非鸟之间对DAA1的选择模式 (正和负选择) 的比较分析.
- 调查DAA1选择模式与DA2位点损失或DAB1.1扩张之间的相关性.
主要成果:
- 通过者拥有DAA1基因的单一副本.
- 与非传人相比,传人DAA1的抗原呈现域 (外显子2) 显示出较弱的阳性选择和更强的负性选择.
- 这些选择模式与DA2位点的丧失无关.
结论:
- 类动物中MHC-IIB (DAB1) 基因的扩张可能会对MHC-IIA (DAA1) 基因施加进化约束.
- 这种约束可能来自DAA1链与多种DAB1链的相互作用.
- 类动物中MHC-II的进化是由MHC-IIB家族内的基因重复和多样化所塑造的.
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