Lu Wei, Zhang Tong, Zhang Quan, Zhang Na, Jia Ling, Ma Sanyuan, Xia Qingyou
State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing 400715, China.
Biological Science Research Center, Southwest University, Chongqing 400715, China.
Insects. 2023 Feb 28;14(3):244. doi: 10.3390/insects14030244.
The highly repetitive and variable fibroin heavy chain () gene can be used as a silkworm identification; however, only a few complete sequences are known. In this study, we extracted and examined 264 gene complete sequences (FibHome) from a high-resolution silkworm pan-genome. The average lengths of the wild silkworm, local, and improved strains were 19,698 bp, 16,427 bp, and 15,795 bp, respectively. All sequences had a conserved 5' and 3' terminal non-repetitive (5' and 3' TNR, 99.74% and 99.99% identity, respectively) sequence and a variable repetitive core (RC). The RCs differed greatly, but they all shared the same motif. During domestication or breeding, the gene mutated with hexanucleotide (GGTGCT) as the core unit. Numerous variations existed that were not unique to wild and domesticated silkworms. However, the transcriptional factor binding sites, such as fibroin modulator-binding protein, were highly conserved and had 100% identity in the gene's intron and upstream sequences. The local and improved strains with the same gene were divided into four families using this gene as a marker. Family I contained a maximum of 62 strains with the optional (Opti-, 15,960 bp) gene. This study provides new insights into variations and silkworm breeding.
高度重复且可变的丝素蛋白重链（）基因可用于家蚕鉴定；然而，已知的完整序列仅有少数几个。在本研究中，我们从高分辨率家蚕泛基因组中提取并检测了264个基因完整序列（FibHome）。野生家蚕、地方品种和改良品种的平均长度分别为19,698 bp、16,427 bp和15,795 bp。所有序列均有一个保守的5'和3'末端非重复序列（5'和3' TNR，分别具有99.74%和99.99%的同一性）以及一个可变的重复核心（RC）。RCs差异很大，但它们都共享相同的基序。在驯化或育种过程中，该基因以六核苷酸（GGTGCT）为核心单元发生突变。存在许多并非野生和驯化家蚕所特有的变异。然而，转录因子结合位点，如丝素蛋白调节剂结合蛋白，在该基因的内含子和上游序列中高度保守且具有100%的同一性。以该基因作为标记，将具有相同基因的地方品种和改良品种分为四个家族。家族I包含最多62个具有可选（Opti-，15,960 bp）基因的品系。本研究为基因变异和家蚕育种提供了新的见解。
