Dissertation Research: The Mechanism of Selection at the Mpi Polymorphism in Semibalanus balanoides

兰德9801563 以前的工作表明，自然选择是重要的，在确定两个不同的遗传变异的一个关键酶负责碳水化合物代谢的潮间带橡子藤壶，Semibalanus balanoides的分布。 藤壶与甘露糖磷酸异构酶（MPI）的一种酶的变体表现出较高的生存率在较热，高潮间带网站，而藤壶与其他MPI变体有较高的生存率在更良性的网站，如低潮间带和海藻下。 拟议的实验将检查藤壶的生存与不同的酶变体在受控条件下在流动的海水缸。 将在析因设计中对温度、干燥和甘露糖的可用性进行操作。 在野外定居在岩石板上的藤壶将被带到实验室，并允许在不同的条件组合下生长。 实验处理前后Mpi酶变体的比例将提供关于自然选择对该酶的作用的明确信息，该酶调节膳食甘露糖（来自海藻）转化为细胞能量的关键步骤。 这项研究将涉及异质环境在维持自然群体遗传变异中的作用。

Rand 9801563 Previous work has shown that natural selection is important in determining the distribution of two different genetic variants of a key enzyme responsible for carbohydrate metabolism in the intertidal acorn barnacle, Semibalanus balanoides. Barnacles with one enzyme variant of mannose phosphate isomerase (Mpi) exhibit higher survivorship in hotter, high-intertidal sites, while barnacles with the other Mpi variant have higher survivorship at more benign sites such as the low intertidal and under seaweeds. The proposed experiments will examine the survivorship of barnacles with different enzyme variants under controlled conditions in a flowing sea water tank. Temperature, desiccation, and the availability of mannose will be manipulated in a factorial design. Barnacles that have settled onto rock slabs in the wild will be brought into the lab and allowed to grow under different combinations of conditions. The proportions of Mpi enzyme variants before and after experimental treatments will provide explicit information about the action of natural selection on this enzyme that regulates a key step in the conversion of dietary mannose (from marine algae) into cellular energy. The research will bear on the role of heterogeneous environments in the maintenance of genetic variation in natural populations.