Dissertation Research: The Importance of the Egg Bank to the Genetics and Demography of a Resident Zooplankton Population

在湖中浮游生物中，水蚤和其他枝角目生物的一个有趣的生殖特征是，它们会产生休眠的卵，这些卵可以在湖泊沉积物中孵化多年。湖泊沉积物中的休眠水蚤卵是土壤中陆生植物“种子库”的动物学模拟物。表层沉积物中的休眠卵是活跃种群遗传多样性的储存库，而深层沉积物中较老的卵是过去种群遗传结构的记录。该项目将分析明尼苏达州一个湖泊沉积物中水蚤卵库的基因组成，以评估该种群是否在自然选择的影响下进化，这些自然选择是由过去40年来每年都储存的虹鳟鱼捕食造成的。它将1)比较过去时期卵库的遗传组成与活跃的居住种群的遗传组成；2)估计地表沉积物中休眠卵的孵化对活跃种群的人口统计学的影响。一个新颖的特点是，在过去的十年里，这个湖一直在监测活跃浮游动物种群的遗传学和人口统计学，从而可以评估活跃种群与休眠卵池之间的联系。目标是将遗传多样性的短期变化与长期的进化动态联系起来。

An intriguing reproductive feature of Daphnia and other Cladocera in lake plankton is that they produce dormant eggs that can hatch after many years in lake sediments. Dormant Daphnia eggs in lake sediment are a zoological analog to the "seed banks" of terrestrial plants in soils. Dormant eggs in surface sediment are a reservoir of genetic diversity for active populations, and older eggs in deeper sediments are a record of genetic structure in past populations. This project will analyze the genetic composition of the Daphnia egg bank in sediments from a Minnesota lake to evaluate whether the population has evolved in response to natural selection imposed by predation by rainbow trout that have been stocked annually for the past 40 years. It will 1) compare the genetic composition of the egg bank at times in the past with that of the active resident population and 2) estimate the effects of hatching of dormant eggs in surface sediment on the demography of the active population. A novel feature is that for the past decade this lake has been monitored the genetics and demography of active zooplankton populations, permitting evaluation of the linkages between active populations and the pool of dormant eggs. The goal is to link short-term variations of genetic diversity to long-term evolutionary dynamics.