Stewart Andrew D, Phillips Patrick C
Department of Biology, University of Texas, Arlington, Texas 76019-0498, USA.
Genetics. 2002 Mar;160(3):975-82. doi: 10.1093/genetics/160.3.975.
Caenorhabditis elegans is an androdioecious nematode composed of selfing hermaphrodites and rare males. A model of male maintenance demonstrates that selfing rates in hermaphrodites cannot be too high or else the frequency of males will be driven down to the rate of spontaneous nondisjunction of the X chromosome. After their outcrossing ability is assessed, males are found to skirt the frequency range in which they would be maintained. When male maintenance is directly assessed by elevating male frequency and observing the frequency change through time, males are gradually eliminated from the population. Males, therefore, appear to reproduce at a rate just below that necessary for them to be maintained. Populations polymorphic for a mutation (fog-2) that effectively changes hermaphrodites into females demonstrate that there is strong selection against dioecy. Factors such as variation in male mating ability and inbreeding depression could potentially lead to the long-term maintenance of males.
秀丽隐杆线虫是一种雄雌同体的线虫，由自交的雌雄同体和罕见的雄性组成。一个雄性维持模型表明，雌雄同体的自交率不能过高，否则雄性的频率将被降低到X染色体自发不分离的速率。在评估它们的杂交能力后，发现雄性处于维持其存在的频率范围边缘。当通过提高雄性频率并观察其随时间的频率变化来直接评估雄性维持时，雄性会逐渐从种群中被淘汰。因此，雄性的繁殖率似乎略低于维持其存在所需的速率。对于一个能有效将雌雄同体转变为雌性的突变（fog-2）具有多态性的种群表明，存在强烈的反对雌雄异体的选择。诸如雄性交配能力的变化和近亲繁殖衰退等因素可能会导致雄性的长期维持。
