雄性秀丽隐杆线虫能提高热胁迫下种群生存优势

Male Caenorhabditis elegans could enhance the population's resistance against heat stress

秀丽隐杆线虫的性别包括自体受精的雌雄同体以及可以与雌雄同体交配的雄性,实验室培养的线虫种群中雄性比例很低,目前尚未发现雌雄同体与雄性线虫杂交后代的遗传优势.为了探讨雄性线虫个体存在的生态意义,本研究比较了热胁迫下两性线虫的生活史变化,以及有无雄性存在的线虫种群应对热胁迫的耐受程度.结果表明:虽然雄性线虫对热胁迫更为敏感,然而当有雄性存在的情况下,整个线虫种群数量在热胁迫后得以更快地恢复,而且与常温培养相比,经常受到热胁迫的线虫种群中雄性的比例可维持在一个较高的水平.这些结果暗示,在多变的自然状态下,秀丽隐杆线虫雄性性别的保留对种群数量的维持有重要的进化意义.

The mating system of Caenorhabditis elegans includes selfing hermaphrodites and the males that cross with hermaphrodites.In lab-cultured C.elegans populations,the proportion of the males is very low,and till now,no detectable fitness of crossed offspring has been found.To explain why the C.elegans conserves a complicated pathway of male development through evolution,we compared the life history of the males and hermaphrodites under heat stress as well as the resistance of the populations with and without males against the heat stress.The results showed that though the life span of the males was more affected by heat stress,as compared with that of the hermaphrodites,the C.elegans populations with the males recovered faster after the stress,and the populations continuously subjected to the heat stress could maintain a higher proportion of the males than the populations cultured at normal temperature.These findings implied that under changeable natural environment,the existence of male C.elegans could be a significant evolutionary strategy for the population survival.