家蚕新突变楔形眼纹(Wes)的遗传与基因定位研究

Genetic Analysis and Gene Localization of a New Mutant Named "Wedge eye-spot" in the Silkworm,Bombyx mori

在家蚕遗传资源系统保存和性状调查中,发现一种新的幼虫眼状纹变异——楔形眼纹(wedge eye-spot,Wes),其特征是:杂合体(Wes/+)成活,幼虫眼状纹只有中间部分,并特化成狭窄的倒三角形,半月纹、星状纹正常;纯合体(Wes/Wes)胚胎后期致死,解剖蚕卵可见胚胎第1、2胸节愈合,第1、2胸足退化,其它部位未见异常。该突变为显性遗传。通过与各染色体标记基因进行连锁分析,发现突变基因Wes在第6染色体上;通过与EKp进行两点测验,显示Wes位于EKp附近,相距约3.0 cM;通过与ve和EKp的三点测验,将Wes基因定位于家蚕连锁图谱第6连锁群的24.3 cM位点,表示为Wes(6-24.3)。

Wedge eye-spot （ Wes）, a new mutant in eye spot of larva, was discovered during the preservation and characteristics investigation of silkworm resources, The heterozygote （ Wes/＋ ） could survive. This eye spot of the larva only appeared at the center and looked like a narrow inverted triangle. The crescent and star spots were normal. The homozygote （Wes/Wes） was lethal during the late embryonic stage. Egg dissection showed that the 1st and 2nd thoracic segments were fused and the 1st and 2nd thoracic legs had degenerated. Other body parts were normal. It was controlled by a dominant mutant gene. Linkage analysis with marker genes on various chromosomes indicated that the mutant eerie Wes is on chromosome 6. The result of two-point test between Wes and E^Kp showed that Wes is located near E^Kp, about 3.0 cM away. Three-point test among Wes, ve and E^Kp showed that the gene locus of Wes is at 24.3 cM on the 6th linkage group in silkworm linkage map.