Singh Gurvachan, Singh Arvind Kumar
Genetics Laboratory, Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005 India.
3 Biotech. 2022 Sep;12(9):195. doi: 10.1007/s13205-022-03257-5. Epub 2022 Jul 28.
species complex includes four monophyletic closely related sympatric species with perfect reproductive isolation in natural conditions. Among these, two species, i.e., and are known to be more prevalent in their occurrence all along their distribution area of Oriental-Australian regions. Genetic characteristics of these two species have been studied by earlier researchers mainly by focusing on their chromosomal polymorphism to gain knowledge pertaining to their evolutionary trend. The present work is one step farther, as we considered isozyme variants of three polymorphic enzymes to envisage genetic differentiation among the different natural populations of these two species, along with, a comparative perusal of their certain population genetic parameters. Natural populations of these two species were sampled from eight places aligned on the north-south axis of India and were subjected to isozyme analysis. The collection of both species and the geographical locations were kept same to avoid the effect of temporal or seasonal factors on the distribution of their allelic frequency. The results of this study clearly indicate that there is intraspecific genetic structuring among the populations of both the species with a distinct steady increase in the level of heterozygosity from north to south. The evolutionary tree in the form of dendrogram depicts two genetically differentiated groups of natural populations, one for north and other for South India. Most essential aspect that has been noticed through this study is the evolutionary trend of these two sympatric species being largely similar all along the north-south axis of India.
物种复合体包括四个单系的、密切相关的同域物种，在自然条件下具有完全的生殖隔离。其中，有两个物种，即[物种名称1]和[物种名称2]，在东洋 - 澳大利亚地区的整个分布区域内更为常见。早期研究人员主要通过关注它们的染色体多态性来研究这两个物种的遗传特征，以获取有关其进化趋势的知识。目前的工作更进一步，我们考虑了三种多态酶的同工酶变体，以设想这两个物种不同自然种群之间的遗传分化，同时，对它们的某些群体遗传参数进行了比较研究。这两个物种的自然种群从印度南北轴线上的八个地点进行采样，并进行同工酶分析。两个物种的样本采集和地理位置保持一致，以避免时间或季节因素对等位基因频率分布的影响。这项研究的结果清楚地表明，两个物种的种群内部都存在遗传结构，杂合度水平从北到南有明显的稳定增加。以树状图形式呈现的进化树描绘了自然种群的两个遗传分化群体，一个代表印度北部，另一个代表印度南部。通过这项研究注意到的最关键方面是，这两个同域物种在印度南北轴线上的进化趋势在很大程度上是相似的。
