The evolutionary origins and consequences of self-fertility in nematodes.
The evolutionary origins and consequences of self-fertility in nematodes.
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DOI：
10.12703/p6-62
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Lin SY
中科院分区：
文献类型：
--
作者：
Ellis RE;Lin SY
在许多线虫物种中，自能生殖的雌雄同体都是从雄性/雌性祖先进化而来的，这种转变在小杆线虫属中发生在三个独立的场合。对小杆线虫的遗传分析表明，雌雄同体的起源需要两种类型的变化：改变性别决定途径，使雌性动物在幼虫发育期间产生精子，以及从性腺产生信号，使这些精子激活卵母细胞并使其受精。C的比较。elegans和C. Briggsae雌雄同体表明，祖先的性别决定途径已经以多种独特的方式改变。这些变化中的一部分必然促成了XX动物精子的产生，另一部分则是修饰性突变，提高了两性生殖的效率。反向遗传实验表明，XX动物通过选择通常在雄性中起作用的两个冗余途径之一来获得激活精子的能力。最后，两性生活方式的采用对生态和性互动以及基因组组织产生了深远的影响。因此，线虫交配系统是阐明新性状起源和研究发育过程对进化变化的影响的理想工具。
Self-fertile hermaphrodites have evolved from male/female ancestors in many nematode species, and this transition occurred on three independent occasions in the genus Caenorhabditis. Genetic analyses in Caenorhabditis show that the origin of hermaphrodites required two types of changes: alterations to the sex-determination pathway that allowed otherwise female animals to make sperm during larval development, and the production of signals from the gonad that caused these sperm to activate and fertilize oocytes. Comparisons of C. elegans and C. briggsae hermaphrodites show that the ancestral sex-determination pathway has been altered in multiple unique ways. Some of these changes must have precipitated the production of sperm in XX animals, and others were modifying mutations that increased the efficiency of hermaphroditic reproduction. Reverse genetic experiments show that XX animals acquired the ability to activate sperm by co-opting one of the two redundant pathways that normally work in males. Finally, the adoption of a hermaphroditic lifestyle had profound effects on ecological and sexual interactions and genomic organization. Thus, nematode mating systems are ideal for elucidating the origin of novel traits, and studying the influence of developmental processes on evolutionary change.