在两个独立的途径中发生的突变足以产生雌雄性线虫
Chris Baldi1, Soochin Cho, Ronald E Ellis
1Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey, Stratford, NJ 08084, USA.
Science (New York, N.Y.)
|December 8, 2009
概括
线虫中雌性性动物的进化可能涉及两个关键的遗传变化. 其中包括一个使XX个体能够产生精子的突变,另一个允许这种精子独立激活的突变.
科学领域:
- 进化遗传学的进化遗传学
- 发育生物学是发展生物学.
- 尼马托德的繁殖策略
背景情况:
- 线虫Caenorhabditis elegans表现出自我肥沃的雌雄性,提供了对祖先角性 (男性/女性) 物种新奇特征演变的见解.
- 相关物种Caenorhabditis remanei具有明显的男性和女性性别,作为研究性别决定和繁殖的遗传基础的模型.
- 了解Caenorhabditis中雌雄性遗传的遗传基础,可以阐明导致这种生殖模式出现的进化途径.
研究的目的:
- 为了研究进化自我肥沃的异性恋的遗传要求在Caenorhabditis属.
- 确定特定的基因突变,可以促进从男性/女性系统向自我生育的雌雄性系统的过渡.
- 为了建模潜在的两步进化过程导致在Caenorhabditis的雌雄性.
主要方法:
- 利用RNA干扰 (RNAi) 来降低参与性别决定和精子激活的特定基因的活动.
- 在Caenorhabditis remanei的XX (雌雄性) 动物中操纵基因表达.
- 评估了操纵的XXX动物产生的精子激活和受精卵细胞的能力.
主要成果:
- 在XX C. remanei动物中降低tra-2基因活性诱导了精子生成,但精子需要男性精液来激活.
- 同时减少tra-2和swm-1基因表达在20世纪的remanei动物导致具有活性的精子的自我生育性双性人.
- 调节C. elegans中的精子激活的基因swm-1被发现对于使操纵的XXX动物实现自我生育至关重要.
结论:
- 在Caenorhabditis中,雌雄性遗传的进化很可能发生在两个不同的遗传步骤中.
- 第一步涉及到性决定途径的突变,导致XX精子生成.
- 第二步涉及像swm-1这样的基因的突变,使精子能够自我激活,从而实现自我生育.
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