Balasubramaniam Sivamani, Soman Misha, Katneni Vinaya Kumar, Tomy Sherly, Gopalapillay Gopikrishna, Vijayan K K
ICAR - Central Institute of Brackishwater Aquaculture, Chennai 600 028, India.
J Genet. 2022;101.
Pearlspot () is one of the most commercially important brackish water fish species widely found along the coastal regions of peninsular India and Sri Lanka. Pearlspot is known for its tender flesh, delectable taste, culinary tourism and highyielding market value. Information on the genetic makeup of stocks/populations is extremely vital as it forms the basis for future genetic studies. For this, we utilized genes of mtDNA of pearlspot populations collected from nine different locations ranging from Ratnagiri in Maharashtra state on the west coast to Chilika in Odisha on the east coast. Sequence analyses of these genes revealed 33 polymorphic sites, which include 17 singleton and 16 parsimony informative sites. Pair-wise genetic differentiation study ( = 0.75) indicated significant (<0.001) differences among all the pairs of stocks except those from Chilika and Nagayalanka. The spatial analysis of molecular variance (SAMOVA) significantly delineated the population into four groups ( = 0.69, = 0.0001), namely northwest (Ratnagiri and Goa); southwest (Mangalore and lakes at Vembanad, Ashtamudi and Vellayani in Kerala); southeast (Pulicat in Tamil Nadu) and northeast (Chilika in Odisha and Nagayalanka in Andhra Pradesh). The above delineation is supported by clades of the phylogenetic tree and also the clusters of median joining haplotype network. The high haplotype diversity (0.84), low nucleotide diversity (0.003), and negative values of Tajima's D (-1.47) and Fu's Fs statistic (-14.89) are characteristic of populations having recently undergone demographic expansion. Mantel test revealed significant isolation by distance. The study identifies highly delineated structured populations with restricted gene flow. If such a stock is overfished, it is highly unlikely that it would recover through migration. For any future breeding programme in this species, it would be desirable to form a base population which incorporates the genetic material from all the locations so that we get a wide gene pool to select from.
珍珠斑（）是印度半岛和斯里兰卡沿海地区广泛分布的最重要的商业咸淡水鱼类之一。珍珠斑以其鲜嫩的鱼肉、美味的口感、烹饪旅游业和高市场价值而闻名。种群的基因组成信息至关重要，因为它构成了未来基因研究的基础。为此，我们利用了从西海岸马哈拉施特拉邦的拉特纳吉里到东海岸奥里萨邦的奇利卡等九个不同地点收集的珍珠斑种群的线粒体DNA基因。对这些基因的序列分析揭示了33个多态性位点，其中包括17个单态位点和16个简约信息位点。成对遗传分化研究（=0.75）表明，除了来自奇利卡和纳加亚兰卡的种群外，所有种群对之间均存在显著差异（<0.001）。分子方差空间分析（SAMOVA）将种群显著划分为四组（=0.69，=0.0001），即西北部（拉特纳吉里和果阿）；西南部（芒格洛尔以及喀拉拉邦文巴纳德、阿什塔穆迪和韦利亚尼的湖泊）；东南部（泰米尔纳德邦的普利卡特）和东北部（奥里萨邦的奇利卡和安得拉邦的纳加亚兰卡）。上述划分得到了系统发育树的分支以及中位数连接单倍型网络的聚类的支持。高单倍型多样性（0.84）、低核苷酸多样性（0.003）以及 Tajima's D（-1.47）和 Fu's Fs 统计量（-14.89）的负值是近期经历过种群扩张的种群的特征。Mantel 检验揭示了显著的距离隔离。该研究确定了具有高度分化结构且基因流动受限的种群。如果这样的种群被过度捕捞，通过迁移恢复的可能性极小。对于该物种未来的任何育种计划，理想的做法是形成一个包含所有地点遗传物质的基础种群，以便我们有一个广泛的基因库可供选择。
