The Silk Road, which derives its name from the trade of silk produced by the domestic silkworm Bombyx mori, was an important episode in the development and interaction of human civilizations. However, the detailed history behind silkworm domestication remains ambiguous, and little is known about the underlying genetics with respect to important aspects of its domestication. Here, we reconstruct the domestication processes and identify selective sweeps by sequencing 137 representative silkworm strains. The results present an evolutionary scenario in which silkworms may have been initially domesticated in China as trimoulting lines, then subjected to independent spreads along the Silk Road that gave rise to the development of most local strains, and further improved for modern silk production in Japan and China, having descended from diverse ancestral sources. We find that genes with key roles in nitrogen and amino acid metabolism may have contributed to the promotion of silk production, and that circadian-related genes are generally selected for their adaptation. We additionally identify associations between several candidate genes and important breeding traits, thereby advancing the applicable value of our resources.
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We thank X. Huang, S. Xu and K. Wang for discussion on the evolutionary analyses, X. Hu, W. Wang, A. Wang, H. Liu, Q. Li and J. Lian for early contributions to the wild silkworm genome sequencing, and L. Chen and X. Wang for assistance with DNA preparation. The research was supported by the National Key Basic Research (973) Program in China (grant 2013CB835200), National Science Foundation of China (grants 31522053, 91631103, 31672370, 31501877 and 31371286), Chinese Academy of Sciences programme (grant 173176001000162007) and Thousand Talents Program of China (to S.Z.).
The authors declare no competing interests.
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Xiang, H., Liu, X., Li, M. et al. The evolutionary road from wild moth to domestic silkworm. Nat Ecol Evol 2, 1268–1279 (2018). https://doi.org/10.1038/s41559-018-0593-4
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