Esox lucius Genome sequencing and assembly. Esox lucius

The pike (Esox lucius) is a northern hemisphere, circumpolar, fresh water species that is typically the top predator in many lakes. It is an important northern recreational fishery. Pike are morphologically diverse and highly adaptable. Despite their wide distribution, pike populations have low levels of polymorphism and divergence, indicative of a recent common ancestor. Pike often function as sentinel species to monitor pollutants in northern waters. Mitochondrial studies have shown that Escosiformes is the closest living order to Salmoniformes. Esociformes, an old lineage with fossils dating back to 70MYA, contains 10 species (pike, muskellunge and mudminnows) of which most literature concerns pike. The genome size for pike is 1.1pg and its karyotype is 2N=50 NF=50, similar to ancestral karyotypes of many teleosts (2N=48-50, FN=48-50). This compares to the much larger Atlantic salmon karyotype of 2N=56-60, NF=74 and genome size =3.1pg. Recent studies are consistent with the pike having a pre-WGD genome and being much closer to salmon than other fish species (zebrafish, medaka, fugu or stickleback).

白斑狗鱼（Esox lucius）是北半球环极地分布的淡水物种，在诸多湖泊中通常充当顶级捕食者。它是北部地区重要的休闲渔业对象。白斑狗鱼形态多样且适应性极强。尽管分布范围广泛，但其种群的多态性与遗传分化水平均较低，这提示其拥有新近的共同祖先。白斑狗鱼常作为指示物种，用于监测北部水域的污染物。线粒体研究表明，狗鱼目（Esociformes）是与鲑形目（Salmoniformes）亲缘关系最近的现生目级类群。狗鱼目是一类古老的演化支，其化石记录可追溯至7000万年前，该目包含10个物种（包括白斑狗鱼、北美狗鱼与泥鳉），其中多数研究文献均以白斑狗鱼为研究对象。白斑狗鱼的基因组大小为1.1皮克（pg），核型为2N=50、NF=50，与多数真骨鱼类的祖先核型（2N=48~50，FN=48~50）相似。与之相比，大西洋鲑的核型（2N=56~60，NF=74）与基因组大小（3.1pg）均显著更大。近期研究证实，白斑狗鱼拥有全基因组复制前的基因组，且相较于斑马鱼、青鳉、河豚或棘鱼等其他鱼类，其与鲑形目鱼类的亲缘关系更为接近。