The proximate determinants of sex ratio in C-elegans populations
The proximate determinants of sex ratio in C-elegans populations
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DOI：
10.1017/s001667230300613x
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发表时间：
2003-04-01
影响因子：
1.5
通讯作者：
Ward, S
中科院分区：
文献类型：
--
作者：
Cutter, AD;Avilés, L;Ward, S
土壤线虫秀丽线虫是一个例子，在这种物种中，自花授粉的两性线虫占主导地位，但有功能的雄性线虫继续存在--允许异种杂交在低水平下坚持下去。由于性染色体不分离或通过与雄性异交而产生雄性后代，两性体可以产生雄性后代。因此，性别决定的遗传学，加上雄性寻找、授精和与两性人受精的效率，将影响这些种群中雄性和异交发生的频率。具有遗传基础的行为和生理特征以及生态特征可能影响雄性生殖成功，从而影响性别比例。由于性别比与雄性生殖成功有关，性别比极大地影响异交率、遗传变异模式以及自然选择在种群内发挥作用的能力。本文用数学模型和实验数据探讨了线虫雄性频率的决定因素。我们讨论了通过性染色体不分离来决定性别的遗传机制在性别比中的作用，以及线虫生活史中的生理成分通过雄性生殖成功而导致性别比变化的影响。最后，我们讨论了在线虫等物种中可能影响性别比例和繁殖系统进化的短期和长期因素。
The soil nematode Caenorhabditis elegans is an example of a species in which self-fertilizing hermaphrodites predominate, but functional males continue to persist - allowing outcrossing to persevere at low levels. Hermaphrodites can produce male progeny as a consequence of sex chromosome non-disjunction or via outcrossing with males. Consequently, the genetics of sex determination coupled with the efficiency by which males find, inseminate and obtain fertilizations with hermaphrodites will influence the frequency at which males and outcrossing occurs in such populations. Behavioural and physiological traits with a heritable basis, as well as ecological characters, may influence male reproductive success and therefore sex ratio. Because sex ratio is tied to male reproductive success, sex ratio greatly affects outcrossing rates, patterns of genetic variation, and the ability of natural selection to act within populations. In this paper we explore the determinants of male frequency in C. elegans with a mathematical model and experimental data. We address the role of the genetic machinery of sex determination via sex chromosome non-disjunction on sex ratio and the influence of physiological components of C. elegans' life history that contribute to variation in sex ratio by way of male reproductive success. Finally, we discuss the short-term and long-term factors that are likely to affect sex ratio and breeding system evolution in species like C. elegans.