Genetic Mapping of Climbing and Mimicry: Two Behavioral Traits Degraded During Silkworm Domestication

Abstract

Behavioral changes caused by domestication in animals are an important issue in evolutionary biology. The silkworm, Bombyx mori, is an ideal fully domesticated insect model for studying both convergent domestication and behavior evolution. We explored the genetic basis of climbing for foraging and mimicry, two degraded behaviors during silkworm domestication, in combination of bulked segregant analysis (BSA) and selection sweep screening. One candidate gene, ASNA1, located in the 3–5 Mb on chromosome 19, harboring a specific non-synonymous mutation in domestic silkworm, might be involved in climbing ability. This mutation was under positive selection in Lepidoptera, strongly suggesting its potential function in silkworm domestication. Nine candidate domesticated genes related to mimicry were identified on chromosomes 13, 21, and 27. Most of the candidate domesticated genes were generally expressed at higher levels in the brain of the wild silkworm. This study provides valuable information for deciphering the molecular basis of behavioral changes associated with silkworm domestication.

Allele‐specific knockouts reveal a role for apontic‐like in the evolutionary loss of larval melanin pigmentation in the domesticated silkworm, Bombyx mori

“…However, TH knockout mutants are predicted to be lethal (Liu et al, 2010; Neckameyer & White, 1993), rendering them difficult to study. Thus, we decided to target yellow‐y (Figure 1B), a melanin synthesis gene that is downstream of TH and functions in melanin synthesis in wide range of insects including B. mori and other Lepidoptera and is predicted to be non‐essential (Chen et al, 2018; Futahashi et al, 2008; Han et al, 2021; Liu et al, 2020; Matsuoka & Monteiro, 2018; Shirai et al, 2021; Wang et al, 2020; Zhang et al, 2017). After confirming the coding sequence annotation (CDS) of the B. mandarina yellow‐y gene, we designed a unique CRISPR‐RNA (crRNA) target site in exon 2 (Figure 2A, Table S1).…”

The Landscapes of Full-Length Transcripts and Splice Isoforms as Well as Transposons Exonization in the Lepidopteran Model System, Bombyx mori

“…B.mori is the only truly domesticated insect. Long-term artificial selection has resulted in significant differences between the domesticated silkworm and its ancestors (Bombyx mandarina) in traits such as silk yield, behavior, body color and so on ( Li, et al, 2020 ; Lu, et al, 2020 ; Wang, et al, 2020 ). Besides, more than 3,000 silkworm strains and >600 mutations with diverse phenotypes are available worldwide which are generated through spontaneous mutation, artificial mutagenesis, or breeding ( Nagaraju et al, 2000 ; Goldsmith, et al, 2005 ; Furdui, et al, 2014 ).…”

“…Subsequently, population genomes and chromosome-level reference genome of the silkworm have been completed one after another (Xia, et al, 2008;Xia, et al, 2009;Xiang, et al, 2018;Kawamoto, et al, 2019). These genome resources play an important role in silkworm domestication history and functional genomics studies (Yang, et al, 2014;Xiang, et al, 2018;Zhu, et al, 2019;Li, et al, 2020;Wang, et al, 2020). Compared with the high-quality genome of the silkworm, the quality of transcripts is poor.…”

Allele-specific knockouts reveal a role for apontic-like in the evolutionary loss of larval pigmentation in the domesticated silkworm, Bombyx mori

“…2017, Fang et al . 2020), larval climbing ability (Wang, Lin, et al . 2020), and mimicry (Wang, Lin, et al .…”

“…The issue of lethality is likely to continue to impede the genetic analysis of pigmentation loss and other domestication-associated traits in B. mori. Recently, several candidate genes associated with domestication in B. mori have been identified using quantitative trait locus (QTL) mapping, including silk production (Li et al 2017, Fang et al 2020, larval climbing ability (Wang, Lin, et al 2020), and mimicry (Wang, Lin, et al 2020). In addition, a recent population genetic analysis identified 300 candidate genes as targets of recent selection in B. mori, some of which are likely to be associated with silk production and voltinism (Xiang et al 2018).…”