Amoutchi Amien Isaac, Kersten Petra, Vogt Asja, Kohlmann Klaus, Kouamelan Essetchi Paul, Mehner Thomas
West African Science Service Centre on Climate Change and Adapted Land Use (WASCAL) Graduate Research Program on Climate Change and Biodiversity Université Felix Houphouet-Boigny Abidjan Côte d'Ivoire.
Leibniz-Institute of Freshwater Ecology and Inland Fisheries Berlin Germany.
Ecol Evol. 2023 Jan 16;13(1):e9724. doi: 10.1002/ece3.9724. eCollection 2023 Jan.
An essential factor for aquatic conservation is genetic diversity or population divergence, which in natural populations reflects the interplay between geographical isolation with restricted gene flow and local evolution of populations. The long geological history of Africa may induce stronger among-population divergence and lower within-population divergence in fish populations of African watersheds. As an example, we studied population structure of the African snakehead fish Our study aimed: (1) to develop a set of highly polymorphic microsatellite markers suitable for the analysis of genetic diversity among and (2) to study the genetic diversity and structure of populations from the West Africa region and mostly from Côte d'Ivoire, with respect to the effects of climate region and geographical distance on the genetic differentiation. A total of 259 specimens from 15 locations of were collected over the West Africa region reflecting a high variability of pairwise geographical distances and variability of hydrological connectivity of the area. We developed a set of 21 polymorphic microsatellite markers for studying population genetics of the fish. The results showed relatively low intragenetic diversity for all the 15 locations, certainly attributable to confinement of fish in segregated catchments, resulting in limited gene flow. We also found evidence for local adaptation processes, suggested by five out of 21 microsatellite loci being under putative selection, according to BAYESCAN analysis. In turn, there was strong genetic differentiation ( > 0.5) among fish from most locations, reflecting the allopatric development in watersheds without hydraulic connectivity. Neighbor-joining dendrogram, Principal Coordinate Analysis, and analysis of ancestral groups by STRUCTURE suggested that the 15 locations can be divided into three clusters, mainly matching the dominant climate zones and the segregation of the watersheds in the region. The distinct genetic structure of the fish from the 15 locations obtained in this study suggests that conservation and sustainable management actions of this fish resource should avoid genetic mixing of potentially locally adapted populations.
水生生物保护的一个关键因素是遗传多样性或种群分化，这在自然种群中反映了地理隔离与有限基因流以及种群局部进化之间的相互作用。非洲漫长的地质历史可能导致非洲流域鱼类种群间更强的分化以及种群内较低的分化。例如，我们研究了非洲鳢的种群结构。我们的研究目标是：（1）开发一套高度多态的微卫星标记，适用于分析……之间的遗传多样性；（2）研究来自西非地区（主要是科特迪瓦）的……种群的遗传多样性和结构，以及气候区域和地理距离对遗传分化的影响。在西非地区的15个地点共采集了259个样本，反映了该地区成对地理距离的高度变异性以及水文连通性的变异性。我们开发了一组21个多态微卫星标记用于研究该鱼类的种群遗传学。结果显示，所有15个地点的遗传多样性相对较低，这肯定归因于鱼类被限制在隔离的集水区内，导致基因流有限。我们还发现了局部适应过程的证据，根据BAYESCAN分析，21个微卫星位点中有5个处于假定选择之下。相应地，大多数地点的鱼类之间存在强烈的遗传分化（FST＞0.5），这反映了没有水力连通性的流域中的异域发育情况。邻接树状图、主坐标分析以及STRUCTURE对祖先群体的分析表明，这15个地点可分为三个聚类，主要与该地区的主要气候带和流域分隔相匹配。本研究中获得的来自15个地点的鱼类独特遗传结构表明，对这种鱼类资源的保护和可持续管理行动应避免潜在局部适应种群的基因混合。
