Department of Zoology, Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8502, Japan.
Field Science Center for Northern Biosphere, Hokkaido University, Tomakomai, 053-0035, Japan.
Sci Rep. 2017 Aug 10;7(1):7773. doi: 10.1038/s41598-017-08362-7.
Body size is a key trait in diversification among animal species, and revealing the gene regions responsible for body size diversification among populations or related species is important in evolutionary biology. We explored the genomic regions associated with body size differences in Carabus japonicus ground beetle populations by quantitative trait locus (QTL) mapping of F hybrids from differently sized parents from two populations using restriction site-associated DNA sequencing and de novo assembly of the beetle whole genome. The assembled genome had a total length of 191 Mb with a scaffold N50 of 0.73 Mb; 14,929 protein-coding genes were predicted. Three QTLs on different linkage groups had major effects on the overall size, which is composed chiefly of elytral length. In addition, we found QTLs on autosomal and X chromosomal linkage groups that affected head length and width, thoracic width, and elytral width. We determined the gene loci potentially related to control of body size in scaffolds of the genome sequence, which contained the QTL regions. The genetic basis of body size variation based on a small number of major loci would promote differentiation in body size in response to selection pressures related to variations in environmental conditions and inter-specific interactions.
体型是动物物种多样化的关键特征，揭示导致群体或相关物种体型多样化的基因区域在进化生物学中很重要。我们通过来自两个群体的不同体型亲本的 F1 杂种的数量性状位点 (QTL) 作图，利用限制性位点相关 DNA 测序和甲虫全基因组从头组装，探索了 Carabus japonicus 步甲种群中与体型差异相关的基因组区域。组装的基因组总长度为 191Mb，支架 N50 为 0.73Mb；预测了 14929 个蛋白质编码基因。三个位于不同连锁群上的 QTL 对整体大小有主要影响，整体大小主要由鞘翅长度组成。此外，我们还发现了位于常染色体和 X 染色体连锁群上的 QTL，这些 QTL 影响头部长度和宽度、胸部宽度和鞘翅宽度。我们在基因组序列的支架中确定了与控制体型相关的基因座，这些基因座包含了 QTL 区域。基于少数主要基因座的体型变化的遗传基础将促进对与环境条件变化和种间相互作用相关的选择压力的体型分化。
