Abstract
Domestic species provides a powerful model for examining genetic mechanisms in the evolution of yield traits. The domestic silkworm (Bombyx mori) is an important livestock species in sericulture. While the mechanisms controlling cocoon yield are largely unknown. Here, using B. mori and its wild relative B. mandarina as intercross parents, 100 BC1 individuals were sequenced by restriction site-associated DNA sequencing (RAD-Seq). The linkage map contained 9,632 markers was constructed. We performed high-resolution quantitative trait locus (QTL) mapping for four cocoon yield traits. A total of 11 QTLs were identified, including one yield-enhancing QTL from wild silkworm. By integrating population genomics and transcriptomic analysis with QTLs, some favourable genes were revealed, including 14 domestication-related genes and 71 differentially expressed genes (DEGs) in the fifth-instar larval silk gland transcriptome between B. mori and B. mandarina. The relationships between the expression of two important candidate genes (KWMTBOMO04917 and KWMTBOMO12906) and cocoon yield were supported by quantitative real-time PCR (qPCR). Our results provide some new insights into the molecular mechanisms of complex yield traits in silkworm. The combined method might be an efficient approach for identifying putative causal genes in domestic livestock and wild relatives.
Highlights
Domestic species provides a powerful model for examining genetic mechanisms in the evolution of yield traits
The domestic silkworm strain Xiafang (D_XF), which is widely used in sericulture production in China, and the wild silkworm (W_AK) were used as the parental mapping lines
Positive correlations were observed among whole cocoon weight (WCW), cocoon shell weight (CSW), and pupal weight (PW)
Summary
Domestic species provides a powerful model for examining genetic mechanisms in the evolution of yield traits. Crops and animals have been under artificial selection, largely directed towards increasing yield, which provides useful model systems to characterize the genetic mechanisms of yield traits. Compared with its wild relatives, long-term artificial breeding and selection have resulted in a high cocoon yield of domestic silkworm[4]. QTL mapping is a method for locating the genetic loci within a whole genome that might contain genes of small effect contributing to yield traits. A large number of single nucleotide polymorphism (SNP) markers are available that can be used for constructing a high-density genetic map, QTL mapping and population genomic analyses[14,15,16,17]. The combination of population genomics and QTL mapping should be an efficient approach for identifying causal genes of domestication-related yield traits[22]. B. mori has been domesticated from the wild mulberry silkworm
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
