太平洋岛屿鸟类中新性染色体的基因组起源和演变
Christina A Muirhead1, Emiliano Martí1, Elsie H Shogren1
1Department of Biology, University of Rochester, Rochester, NY 14627.
概括
在太平洋岛屿鸟类中新发现的新性染色体揭示了新W染色体的快速演变. 这涉及自体转位,逆转和退化,为性染色体进化提供了洞察力.
科学领域:
- 进化基因组学 进化基因组学
- 性染色体进化 性别染色体进化
- 鸟类遗传学 鸟类遗传学
背景情况:
- 性染色体进化的标准模型依赖于古代的XY或ZW系统.
- 年轻的新性染色体,由自身转位形成,为早期进化事件提供了洞察力.
- 直到最近,新性染色体在像鸟类这样的雌性异性异性种群中被认为是罕见的.
研究的目的:
- 研究两种太平洋岛屿鸟类新发现的新Z和新W性染色体的进化基因组学.
- 通过比较分析了解性染色体进化的早期阶段.
主要方法:
- 进化基因组学的比较.
- 对 *Myzomela tristrami* 和 *M. cardinalis* 的性别染色体结构和含量进行分析.
主要成果:
- 大约85%的自体 (chr5) 转移到19-21万年前的祖先性染色体的伪自体区域 (PAR).
- 一个大的反转形成了一个非重组 (NR) 的新西地区和一个新PAR,随后又出现了七个额外的反转.
- 新W染色体显示了内源性逆转录病毒入侵的证据,减少了选择疗效和功能退化.
结论:
- 这些发现与标准性染色体进化模型的一些预测一致,但也突出了新性染色体进化的独特方面.
- 自体转位之后的反转和退行形成了新W染色体.
- 在祖先的W染色体上逆转移素的积累可能加速了新W的进化和退化.
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