RUI: Experimental Investigation of Ecological and Genetic Correlates of Parthenogenetic and Reproduction in a Fresh Water Snail

RUI：淡水蜗牛孤雌生殖和繁殖的生态和遗传相关性的实验研究

• 批准号: 9629287
• 负责人: Steven Johnson
• 金额: $ 10.31万
• 依托单位: University of New Orleans
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9629287&HistoricalAwards=false
• 关键词: RUI; Experimental; Investigation; Ecological; Genetic

9629287 Johnson One of the outstanding problems in biology today is why sexual reproduction is so common in many organisms when there appear to be considerable costs to sexual reproduction relative to alternatives like parthenogenetic reproduction (individuals develop from unfertilized eggs). Of the many hypotheses developed to explain the widespread maintenance of sexual reproduction in many organisms, the parasite theory appears to be the most plausible and testable. According to the parasite theory, sexual reproduction is favored over parthenogenetic reproduction in hosts under high risk of parasitism because sexual offspring may be less susceptible to infection by parasites. Parthenogenesis should be favored when there is minimal risk of parasitism. Parthenogens may, however, suffer high levels of parasitism if parasites recolonize parthenogenetic populations with limited genetic variation. Field and laboratory experiments will be undertaken to distinguish among the causes of higher levels of parasitic flatworms in parthenogenetic population of the North American freshwater snail, Campeloma decisum. Parthenogenesis may be favored due to sperm limitation caused by a trematode worm or, alternatively, parthenogens may have had an advantage colonizing lakes and rivers after glaciers receded. High parasitism results from lack of genetic variation in asexual populations. Field and laboratory experiments will test the prediction from the parasite theory that sexual individuals should experience lower levels of infection and greater variation in infection relative to parthenogenetic individuals. The research outlined above should provide important insights into how epidemic diseases spread in organisms with limited amounts of genetic variation. Two important groups of organisms that may have limited genetic variation are inbred lines of agricultural crops and small populations of endangered plants and animals.

9629287约翰逊 当今生物学中的一个突出问题是，为什么有性生殖在许多生物中如此普遍，而相对于单性生殖（个体从未受精的卵子发育而来）等替代方法，有性生殖似乎有相当大的成本。 在解释许多生物体广泛维持有性生殖的许多假说中，寄生虫理论似乎是最合理和最可检验的。 根据寄生虫理论，在高寄生风险的宿主中，有性生殖比孤雌生殖更受青睐，因为有性后代可能对寄生虫感染不太敏感。 当寄生的风险最小时，单性生殖应该受到青睐。 然而，孤雌生殖可能会遭受高水平的寄生，如果寄生虫tenonize孤雌生殖种群有限的遗传变异。 将进行实地和实验室实验，以区分北美淡水蜗牛（Campeloma decisum）孤雌生殖种群中寄生扁虫水平较高的原因。 单性生殖可能是有利的，由于精子限制所造成的吸虫蠕虫，或者，单性生殖可能有一个优势，殖民湖泊和河流后，冰川消退。 高寄生率是由于无性种群缺乏遗传变异造成的。 田间和实验室实验将检验寄生虫理论的预测，即有性个体相对于单性个体应经历较低的感染水平和较大的感染变异。 上面概述的研究应该为流行病如何在遗传变异有限的生物体中传播提供重要的见解。 可能具有有限遗传变异的两个重要生物群体是农作物的近交系和濒危动植物的小种群。