Have scientists unlocked genetic secret for finer silk? - study

• Author: SARA WEINSTEIN
• Published date: 04 October 2022
• Publication title: Jerusalem Post, The: Web Edition Articles (Israel)

Due to the limited availability of wild silkworms in the past, many trait-associated sites were missing in the genome. But by building a high-resolution pan-genome dataset that represents almost the entire genomic content in the silkworm, BGI Genomics, along with Southwest University, the State Key Laboratory of Silkworm Genome Biology and other partners, became the first to digitize the silkworm gene pool. Their research facilitates functional genomic research, promotes precise breeding and enables more silk use cases

The study was published in the peer-reviewed journal Nature Communications on September 24.

"This ushers in a new era for silkworm basic research and molecular breeding and provides guidelines for the large-scale pan-genome research of other species."

Xiaoling Tong

"Genomic data greatly accelerated the development of biological research in the last two decades," writes lead study author Xiaoling Tong. "Recently, the focus of genome research has shifted from a single reference genome to a pan-genome approach that provides greater insights into the entire genomic content of a species."

The team deeply re-sequenced 1,078 silkworms and assembled long-read genomes on 545 of the samples. The resulting pan-genome dataset is the largest long-read pan-genome in the world for plants and animals, including the most comprehensive information on the genomes of wild and domestic silkworms.

The research findings also provided insights into artificial selection, or domestication and breeding, and ecological adaptation.

From where do domestic silkworms originate?

Bombyx mori, the domestic silkworm, was domesticated from B. mandarina, the wild mulberry silkworm. Due to lacking biological evidence, the domestication origin remains in question.

This study revealed that endemic species from China's lower and middle Yellow River region are distributed at the base of the domestic silkworm branch on the evolutionary tree. From this, the researchers suggest that B. mori originated in this region. Providing support to this suggestion is the half cocoon excavated at Xiyin Village, Xia County, Shanxi Province in 1926, and the stone-carved silkworm pupa excavated at Shicun in the same county in 2019.

Since the 1990s, silkworm breeding has remained in gridlock.

Genetics of silkworms

THE TEAM identified 468 domestication-associated genes and 198 improvement-associated genes. Of these, 264 and 185 are newly found. Solving the unresolved issues in silkworm breeding, these...