Teotónio Henrique, Manoel Diogo, Phillips Patrick C
Centro de Biologia do Desenvolvimento, Instituto Gulbenkian de Ciência, Apartado 14 P-2781-901 Oeiras, Portugal.
Evolution. 2006 Jun;60(6):1300-5.
The evolution of breeding systems results from the existence of genetic variation and selective forces favoring different outcrossing rates. In this study we determine the extent of genetic variation for characters directly related to outcrossing, such as male frequency, male mating ability, and male reproductive success, in several wild isolates of the nematode Caenorhabditis elegans. This species is characterized by an androdioecious breeding system in which males occur with hermaphrodites that can either self-fertilize or outcross with males. We find genetic variation for all characters measured, but also find that environmental variation is a large fraction of the total phenotypic variance. We further determine the existence of substantial genetic variation for population competitive performance in several laboratory environments. However, these measures are uncorrelated with outcrossing characters. The data presented here contribute to an understanding of male maintenance in natural populations through their role in outcrossing.
繁育系统的进化源于遗传变异的存在以及有利于不同异交率的选择压力。在本研究中，我们测定了线虫秀丽隐杆线虫几个野生分离株中与异交直接相关的性状的遗传变异程度，如雄虫频率、雄虫交配能力和雄虫繁殖成功率。该物种的特征是雄雄同体的繁育系统，其中雄虫与既能自体受精又能与雄虫异交的雌雄同体共存。我们发现所测量的所有性状都存在遗传变异，但也发现环境变异在总表型变异中占很大比例。我们进一步确定了在几个实验室环境中，群体竞争性能存在大量遗传变异。然而，这些指标与异交性状不相关。本文所呈现的数据有助于通过雄虫在异交中的作用来理解其在自然种群中的维持。
