Comparative Analysis of the Shared Sex-Determination Region (SDR) among Salmonid Fishes.
Comparative Analysis of the Shared Sex-Determination Region (SDR) among Salmonid Fishes.
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DOI：
10.1093/gbe/evv123
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发表时间：
2015-06-25
影响因子：
3.3
通讯作者：
Brown KH
中科院分区：
文献类型：
--
作者：
Faber-Hammond JJ;Phillips RB;Brown KH
鲑科鱼类为研究年轻性染色体的进化提供了一个极好的模型。在虹鳟属中，至少有六对独立的性染色体已经进化，许多是个别物种所独有的。这种变异是由性别决定基因sdY在整个鲑鱼基因组中的移动造成的。虽然已知sdY定义了鲑鱼的性别分化，但由于性别决定区（SDR）周围的重复元件、rDNA序列和转座子的高频率，其在整个基因组中的运动机制仍然难以捉摸。尽管存在这些困难，但已经报道了来自虹鳟鱼和大西洋鲑鱼的含有sdY区域的细菌人工染色体（BAC）文库克隆。在这里，我们报告了这些BAC的序列，以及通过基因组步行方法获得的奇努克已知SDR的扩展序列。比较分析使我们能够研究三个独特的鲑鱼Y染色体的重叠SDR，以确定物种之间存在的具体内容，大小和变异。我们发现大约4.1 kb的orthopathic序列共同的所有三个物种，其中包含必要的雄性化的遗传内容。该地区包含转座因子，可能是负责整个鲑鱼基因组的SDR的易位，我们研究每个潜在的机械作用。
Salmonids present an excellent model for studying evolution of young sex-chromosomes. Within the genus, Oncorhynchus, at least six independent sex-chromosome pairs have evolved, many unique to individual species. This variation results from the movement of the sex-determining gene, sdY, throughout the salmonid genome. While sdY is known to define sexual differentiation in salmonids, the mechanism of its movement throughout the genome has remained elusive due to high frequencies of repetitive elements, rDNA sequences, and transposons surrounding the sex-determining regions (SDR). Despite these difficulties, bacterial artificial chromosome (BAC) library clones from both rainbow trout and Atlantic salmon containing the sdY region have been reported. Here, we report the sequences for these BACs as well as the extended sequence for the known SDR in Chinook gained through genome walking methods. Comparative analysis allowed us to study the overlapping SDRs from three unique salmonid Y chromosomes to define the specific content, size, and variation present between the species. We found approximately 4.1 kb of orthologous sequence common to all three species, which contains the genetic content necessary for masculinization. The regions contain transposable elements that may be responsible for the translocations of the SDR throughout salmonid genomes and we examine potential mechanistic roles of each one.