Data from: The genetic architecture of growth rate in juvenile Takifugu species.

Closely related species have often evolved dramatic differences in body size. Takifugu rubripes (fugu) is a large marine pufferfish whose genome has been sequenced, whereas T. niphobles is the smallest species among Takifugu. We show that, unsurprisingly, the juvenile growth rate of T. rubripes is higher than that of T. niphobles in a laboratory setting. We produced F2 progenies of their F1 hybrids and found one quantitative trait locus (QTL) significantly associated with variation in juvenile body size. This QTL region (3.5 Mb) contains no known genes directly related to growth phenotype (such as IGFs) except Fgf21, which inhibits growth hormone signaling in mouse. The QTL in Takifugu spp. is distinct from the region previously known to control body size variations in stickleback or tilapia. Our results suggest that in the fish tested herein, genomic regions underlying body size evolution might have different genetic origins. They also suggest that many diverse traits in Takifugu spp. are amenable to genetic mapping.

亲缘关系相近的物种往往会演化出体型上的显著差异。红鳍东方鲀（Takifugu rubripes，俗称fugu）是一种大型海洋河豚，其基因组已完成测序；而星点东方鲀（Takifugu niphobles）则是东方鲀属（Takifugu）中体型最小的物种。本研究证实，不出所料，在实验室培养条件下，红鳍东方鲀的幼体生长速率高于星点东方鲀。我们通过杂交获得双亲的子一代（F1）群体，进一步培育得到子二代（F2）分离群体，并成功定位到一个与幼体体型变异显著相关的数量性状位点（quantitative trait locus, QTL）。该QTL区域（长度3.5 Mb）中，除了在小鼠中可抑制生长激素信号通路的Fgf21外，未发现其他与生长表型直接相关的已知基因（如胰岛素样生长因子（IGFs））。东方鲀属的该QTL区域，与此前报道的调控刺鱼（stickleback）或罗非鱼（tilapia）体型变异的基因组区域并不相同。本研究结果提示，在本次检测的鱼类类群中，驱动体型演化的基因组区域可能具有不同的遗传起源。同时，本研究结果还表明，东方鲀属的多种复杂性状均可通过遗传作图技术进行遗传解析。