DNA Polymorphism and Divergence of Glucose-6-Phosphate Isomerase in Five Species of Invertebrates

在几种动物中，葡萄糖-6-磷酸异构酶（Gpi）的等位基因频率在南北地区存在差异。自然选择可能是这些地理模式的原因，一个等位基因在温暖的环境中受到青睐，而另一个等位基因在寒冷的环境中受到青睐。然而，要排除等位基因频率的地理模式的其他解释是很困难的，比如在孤立的种群中频率的随机漂移。科学家将对五种无脊椎动物的Gpi基因进行测序，并进行一些统计测试，以确定自然选择对该基因的影响是否重要。这些数据还将有助于确定近亲物种之间的差异是由于自然选择，还是由于不受选择影响的随机突变的积累。该项目的结果将解决自然种群遗传学中的两个基本问题：自然选择在决定一个物种内基因频率方面有多重要，以及自然选择在决定物种间差异方面有多重要。当观察到物种内部或物种之间蛋白质和DNA序列的差异时，了解这种差异是自然选择引起的，还是由于不受选择影响的突变引起的，对于广泛的遗传研究具有明显的重要性。此外，该研究可能为生物种群适应不同环境的遗传和生化基础提供见解。这对于了解物种如何应对不断变化的环境、适应或灭绝非常重要，以及设计新的基因工程生物。R T$ & (*,；0 2 4 6 8: ！!!!我的天，我的天，我的天！!F L T T (Times New Roman Symbol & & Arial g g g " h E c E c E k 7 Crystal Blackshear水晶Blackshear

9317949 McDonald In several species of animals, the enzyme glucose-6-phosphate isomerase (Gpi) has differences in allele frequency between northern and southern locations. Natural selection may be the cause of these geographic patterns, with one allele being favored in warm environments and another allele in cool environments. It has been difficult, however, to rule out other explanations for geographic patterns in allele frequency, such as random drift of frequencies in isolated populations. The DNA for the Gpi gene in five species of invertebrates will be sequenced, and several statistical tests will be done which can determine whether natural selection is important in affecting the gene. The data will also help determine whether the differences between closely related species are due to natural selection, or to the accumulation of random mutations that are not affected by selection. The results of the project will address two basic questions in the genetics of natural populations: how important natural selection is in determining gene frequencies within a species, and how important natural selection is in determining the differences between species. When differences are observed within or between species in protein and DNA sequences, it is of obvious importance for a wide range of genetic researches to understand whether natural selection has caused the variation, or whether the variation is due to mutations that are unaffected by selection. In addition, the research may provide insights into genetic and biochemical basis by which populations of organisms adapt to different environments. This is importa nt to understanding how species will respond to changing environments, adapting or going extinct, and in designing new genetically engineered organisms. R T " $ & ( * , . 0 2 4 6 8 : ! ! ! ! @ B D F H J L N P R T ! ! F L T T ( Times New Roman Symbol & Arial g g g " h E c e c e k 7 Crystal Blackshear Crystal Blackshear