Data from: Barriers to gene flow in the marine environment: insights from two common intertidal limpet species of the Atlantic and Mediterranean

Knowledge of the scale of dispersal and the mechanisms governing gene flow
in marine environments remains fragmentary despite being essential for
understanding evolution of marine biota and to design management plans. We
use the limpets Patella ulyssiponensis and Patella rustica as models for
identifying factors affecting gene flow in marine organisms across the
North-East Atlantic and the Mediterranean Sea. A set of allozyme loci and
a fragment of the mitochondrial gene cytochrome C oxidase subunit I were
screened for genetic variation through starch gel electrophoresis and DNA
sequencing, respectively. An approach combining clustering algorithms with
clinal analyses was used to test for the existence of barriers to gene
flow and estimate their geographic location and abruptness. Sharp breaks
in the genetic composition of individuals were observed in the transitions
between the Atlantic and the Mediterranean and across southern Italian
shores. An additional break within the Atlantic cluster separates samples
from the Alboran Sea and Atlantic African shores from those of the Iberian
Atlantic shores. The geographic congruence of the genetic breaks detected
in these two limpet species strongly supports the existence of
transpecific barriers to gene flow in the Mediterranean Sea and
Northeastern Atlantic. This leads to testable hypotheses regarding factors
restricting gene flow across the study area.

尽管了解海洋生物群的进化及制定管理计划均需掌握海洋环境中基因流的扩散规模与调控机制，但目前相关认知仍较为零散。本研究以帽贝Patella ulyssiponensis和Patella rustica为模型，旨在识别影响东北大西洋与地中海区域海洋生物基因流的关键因素。研究分别通过淀粉凝胶电泳（starch gel electrophoresis）和DNA测序技术，对一组等位酶位点（allozyme loci）及一段线粒体细胞色素C氧化酶亚基I（cytochrome C oxidase subunit I）基因片段的遗传变异进行检测。结合聚类算法（clustering algorithms）与梯度分析（clinal analyses）的方法，本研究验证了基因流障碍的存在，并估算其地理分布与突变程度。结果显示，在大西洋与地中海的过渡区域及意大利南部海岸，个体遗传组成存在明显断裂；此外，大西洋集群内部亦存在一处断裂，将阿尔沃兰海与非洲大西洋海岸样本同伊比利亚大西洋海岸样本分隔开来。两种帽贝物种中检测到的基因断裂在地理分布上具有一致性，这有力支持了地中海与东北大西洋区域存在跨物种基因流障碍的结论，进而为探究研究区域内限制基因流的因素提供了可验证的假设。