Institute of Natural and Environmental Sciences, University of Hyogo, Sanda, Hyogo, 669-1546, Japan.
Division of Nature and Environmental Management, Museum of Nature and Human Activities, Sanda, Hyogo, 669-1546, Japan.
BMC Genomics. 2021 Aug 12;22(1):615. doi: 10.1186/s12864-021-07908-4.
Telmatochromis temporalis is a cichlid fish endemic to Lake Tanganyika. The normal and dwarf morphs of this fish are a clear example of ongoing ecological speciation, and body size plays an important role in this speciation event as a magic trait. However, the genetic basis underlying this trait has not been studied.
Based on double-digested restriction-site associated DNA (ddRAD) sequencing of a hybrid cross between the morphs that includes F0 male, F0 female, and 206 F2 individuals, we obtained a linkage map consisting of 708 ddRAD markers in 22 linkage groups, which corresponded to the previously reported Oreochromis niloticus chromosomes, and identified one significant and five suggestive quantitative trait loci (QTL) for body size. From the body-size distribution pattern, the significant and three of the five suggestive QTL are possibly associated with genes responsible for the difference in body size between the morphs.
The QTL analysis presented here suggests that multiple genes, rather than a single gene, control morph-specific body size. The present results provide further insights about the genes underlying the morph specific body size and evolution of the magic trait during ecological speciation.
坦噶尼喀慈鲷是一种生活在坦噶尼喀湖的慈鲷鱼类。该鱼类的正常形态和侏儒形态是正在进行的生态物种形成的一个明显例子，而体型大小作为一种神奇特征在这一物种形成事件中起着重要作用。然而，这一特征的遗传基础尚未得到研究。
基于对包括 F0 雄性、F0 雌性和 206 个 F2 个体的形态之间的杂交进行的双酶切限制位点相关 DNA（ddRAD）测序，我们获得了一个连锁图谱，该图谱由 708 个 ddRAD 标记组成，位于 22 个连锁群中，与先前报道的奥利亚罗非鱼染色体相对应，并鉴定出一个显著的和五个暗示的体型大小数量性状位点（QTL）。从体型分布模式来看，显著的和五个暗示的 QTL 中的三个可能与导致形态体型差异的基因有关。
这里进行的 QTL 分析表明，多个基因而不是单个基因控制着形态特异性的体型。本研究结果为生态物种形成过程中体型大小和神奇特征进化的形态特异性体型的基因提供了进一步的认识。
