Poćwierz-Kotus A, Kijewska A, Petereit C, Bernaś R, Więcaszek B, Arnyasi M, Lien S, Kent M P, Wenne R
Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland.
GEOMAR Helmholtz Centre for Ocean Research Kiel, Research Unit: Evolutionary Ecology of Marine Fish, 24105 Kiel, Germany.
Mar Genomics. 2015 Feb;19:17-22. doi: 10.1016/j.margen.2014.05.010. Epub 2014 Jun 5.
The Baltic is a semi-enclosed sea characterised by decreasing salinity in the eastern and northern direction with only the deeper parts of the southern Baltic suitable as spawning grounds for marine species like cod. Baltic cod exhibits various adaptations to brackish water conditions, yet the inflow of salty North Sea water near the bottom remains an influence on the spawning success of the Baltic cod. The eastern Baltic population has been very weakly studied in comparison with the western population. The aim of this study is to demonstrate for the first time genetic differentiation by the use of a large number of SNPs between eastern and western Baltic populations existing in differentiated salinity conditions. Two cod samples were collected from the Bay of Gdańsk, Poland and one from the Kiel Bight, Germany. Samples were genotyped using a cod derived SNP-array (Illumina) with 10 913 SNPs. A selection of diagnostic SNPs was performed. A set of 7944 validated SNPs were analysed to assess the differentiation of three samples of cod. Results indicated a clear distinctness of the Kiel Bight from the populations of the eastern Baltic. FST comparison between both eastern samples was non-significant. Clustering analysis, principal coordinates analysis and assignment test clearly indicated that the eastern samples should be considered as one subpopulation, well differentiated from the western subpopulation. With the SNP approach, no differentiation between groups containing 'healthy' and 'non-healthy' cod individuals was observed.
波罗的海是一个半封闭海域，其特点是盐度在东部和北部方向逐渐降低，只有波罗的海南部较深的区域适合作为鳕鱼等海洋物种的产卵地。波罗的海鳕鱼对微咸水条件表现出各种适应性，但北海底部咸水的流入仍然影响着波罗的海鳕鱼的产卵成功率。与西部种群相比，对波罗的海东部种群的研究非常少。本研究的目的是首次通过使用大量单核苷酸多态性（SNP）来证明处于不同盐度条件下的波罗的海东部和西部种群之间的遗传分化。从波兰格但斯克湾采集了两份鳕鱼样本，从德国基尔湾采集了一份样本。使用具有10913个SNP的鳕鱼衍生SNP芯片（Illumina）对样本进行基因分型。进行了诊断性SNP的选择。分析了一组7944个经过验证的SNP，以评估三个鳕鱼样本的分化情况。结果表明，基尔湾的鳕鱼与波罗的海东部种群明显不同。两个东部样本之间的FST比较无显著差异。聚类分析、主坐标分析和分配测试清楚地表明，东部样本应被视为一个亚种群，与西部亚种群有明显分化。采用SNP方法，未观察到包含“健康”和“不健康”鳕鱼个体的组之间存在分化。
