Molecular Population Genetics of a Phosphoglucose Isomerase Polymorphism: Testing Hypotheses of Balancing Selection and Trans-specific Polymorphism

哈里森9318472国家群体(包括人类群体)通常在编码可溶性酶的基因上包含大量变异。这种酶变异的功能意义仍然是一个相当有争议的问题。自然种群中的酶变体在功能特性上是否有所不同？如果是这样的话，是什么力量在种群内保持变异。这个项目的重点是使用不同等位基因形式的磷酸葡萄糖异构酶(PGI)的DNA测序来确定是什么在维持昆虫物种内的酶多样性。前列环素在碳水化合物代谢中占有中心地位。催化葡萄糖-6-磷酸和果糖-6-磷酸的相互转化。这项研究的第一个目标是描述两种蟋蟀的PGI基因的结构，这两种蟋蟀都是PGI的变种，都具有相同的等位基因变异(等位酶)阵列。然后将对这两个物种中每个等位变异的代表进行测序。特别令人感兴趣的是，区分等位酶类别的氨基酸差异在两个物种中是否部分或全部相同，以及所观察到的氨基酸差异是否可能通过平衡选择在种群中保持。这一结果将阐明可溶性酶遗传变异的重要性这一一般性问题。这一问题的解决对于理解人类种群中遗传变异的意义以及与长期保存遗传资源有关的问题具有重要意义。

HARRISON 9318472 National Populations (including human populations) often contain large amounts variation at genes coding for soluble enzymes. The functional significance of this enzyme variation remains a matter of considerable debate. Do enzyme variants in natural populations differ in their functional properties? If so, what forces maintain variation within populations. This project focuses on using DNA sequencing of different allelic forms of the enzyme phosphoglucose isomerase (PGI) to determine what is acting to maintain enzyme variation within species of insects. PGI occupies a central position in carbohydrate metabolism. Catalyzing the interconversion of glucose-6-phosphate and fructose-6-phosphate. The first goal of this research is to characterize the structure of the Pgi gene in two species of crickets, which are both variable for PGI and which have the "same" array of allelic variants (allozymes). Representatives of each of the allelic variants in the two species will then be sequenced. Of particular interest is whether some or all of the amino acid differences that distinguish the allozyme classes are identical in the two species and whether observed amino acid differences are likely maintained in populations by balancing selection. The results will shed light on the general question of the significance of genetic variation for soluble enzymes. Resolution of this issue has implications for understanding the significance of genetic variation in human populations and for questions related to long-term conservation of genetic resources.