雌性鱼在性选择策略中计数单基因,解释MHC多态性
T B Reusch1, M A Häberli, P B Aeschlimann
1Max Planck Institute for Limnology, Department of Evolutionary Ecology, Postfach 165, 24306 Plön, Germany. reusch@mpil-ploen.mpg.de
Nature
|November 20, 2001
概括
雌性鱼更喜欢具有更多样化的免疫基因 (MHCIIB类等位基因) 的雄性,以增强后代的寄生虫抵抗力. 他们并没有避免与遗传上相似的雄性交配,这表明基因对象计数是选择伴侣的关键.
科学领域:
- 进化生物学是进化的生物学.
- 行为生态学 行为生态学
- 免疫遗传学 免疫遗传学
背景情况:
- 在自然种群中,主要基因相容性复合 (MHC) 基因中保持高遗传多样性仍然是一个关键的进化问题.
- 拟议的机制包括性选择,病原体的频率依赖选择和异胞优势.
- 性选择可能涉及避免近亲繁殖或增强后代寄生虫抵抗力的策略.
研究的目的:
- 研究MHC基因在自然种群中的性选择和伴侣选择中的作用.
- 测试伴侣偏好是否是由MHC基因型不相似性 (避免杂交) 或MHC等位基因多样性 (寄生虫耐药性) 驱动的.
- 为了确定"等位基因计数"与三脊的不分类性交配策略的相对重要性.
主要方法:
- 从湖泊系统中利用了野生捕获的三脊鱼 (Gasterosteus aculeatus).
- 根据男性气味评估女性的伴侣偏好.
- 量化MHCIIB类的等位基因数和潜在伴侣的基因型相似性.
主要成果:
- 怀孕的雌性带鱼更喜欢拥有更高数量的MHCIIB类等位基因的雄性的气味.
- 女性没有表现出对MHC基因型与自身不同的男性的偏好.
- 结果支持一种与寄生虫耐药性相关的"等位基数计数"策略,而不是为了避免近亲繁殖而进行分类交配.
结论:
- 在三脊鱼中,与MHC相关的性选择有利于通过基于MHC等位基多样性的伴侣选择来增加后代的免疫能力.
- "等位基数计数"策略,最大限度地提高后代对病原体的抵抗力,似乎比通过这种物种的MHC不相似性避免内生更为重要.
- 这些发现有助于理解维护脊椎动物中MHC多态性的进化力量.
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