National Research Council of Italy, Institute for the Study of the Anthropic Impacts and the Sustainability of the Marine Environment (IAS) via De Marini 6, 16149 Genoa, Italy.
Department of Arctic and Marine Biology, UIT The Arctic University of Norway, NO-9037 Tromsø, Norway.
Genes (Basel). 2020 Dec 18;11(12):1515. doi: 10.3390/genes11121515.
The ice cod (Peters, 1872) is one of the few fish species endemic to the Arctic. With a circumpolar distribution, the species is confined to the fjords and shelves of the Arctic seas. Biological information on is scarce, with genomic information restricted to microsatellites. Within the frame of the TUNU-Programme: Arctic Ocean Fishes-Diversity, Adaptation and Conservation, we studied at the chromosomal level to explore fish diversity and evolutionary aspects. The analysis of over 50 individuals from the Northeast Greenland fjords between latitudes 71°09' N and 76°42' N revealed a remarkable intraspecific diversity epitomized by chromosome numbers spanning from 28 to 33, the occurrence of putative B chromosomes, and diversified patterns of distribution of heterochromatin and rDNAs. The number of B chromosomes followed a latitudinal gradient from 0-2 in the north to 2-5 in the south. Considering the benthic and rather stationary life history of this species, the observed chromosomal differences might have arisen independently, possibly driven and/or fostered by the dynamics of repetitive sequences, and are being fixed in relatively isolated fjord populations. The resulting latitudinal cline we observe today might have repercussions on the fate of local populations facing the ongoing climate-driven environmental changes.
北极鳕鱼（Peters，1872）是少数几种特有的北极鱼类之一。该物种分布于环极地区，局限于北极海域的峡湾和大陆架。关于北极鳕鱼的生物学信息很少，基因组信息仅限于微卫星。在 TUNU 计划：北极海洋鱼类——多样性、适应和保护的框架内，我们在染色体水平上研究了北极鳕鱼，以探索鱼类多样性和进化方面的问题。对北纬 71°09'N 至 76°42'N 的东北格陵兰峡湾中超过 50 个个体的分析显示出显著的种内多样性，表现在染色体数量从 28 到 33 不等，存在可能的 B 染色体，异染色质和 rDNAs 的分布模式多样化。B 染色体的数量呈现从北到南从 0-2 到 2-5 的纬度梯度。考虑到该物种的底栖和相对静止的生活史，观察到的染色体差异可能是独立产生的，可能是由重复序列的动态驱动和/或促进的，并在相对孤立的峡湾种群中固定下来。我们今天观察到的这种纬度梯度可能会对面临正在进行的气候变化驱动的环境变化的当地种群的命运产生影响。
