Identification of 2nd chromosome region translocated onto the W chromosome by RFLP with EST-cDNA clones in the Gensei-kouken strains of the mulberry silkworm, Bombyx mori L

Genetics and Molecular Biology

Sivaramakurup Sreekumar¹  Keiko Kadono-okuda¹  Ken-ichi Nagayasu¹  Wajiro Hara¹ 

[1] ,National Institute of Agrobiological Sciences Insect Genome Laboratory Tsukuba Ibaraki ,Japan

关键词: sex-limited strains;    chromosomal translocation;    cDNA markers;    restricted fragment length polymorphism;    mulberry silkworm;   

DOI  :  10.1590/S1415-47572009005000105

来源: SciELO

【 摘 要 】

In silkworms, sex-limited strains are either obtained spontaneously or induced by X-rays or gamma rays. When a fragment of an autosome carrying a dominant allele of those genes responsible for certain characters is translocated onto a W chromosome, the female of the successive generations will express these phenotypic characters and sex discrimination can be facilitated. Gensei-kouken strains are sex-limited strains of silkworms developed by irradiating the pupae with gamma rays, by which a portion of the second chromosome is translocated onto the W chromosome. In these improved strains, the females are yellow-blooded and spin yellow cocoons. By using the EST-cDNA clones mapped on the Z chromosome, we identified the sex according to the polymorphic banding pattern or intensity of the signals. Furthermore, by using the clones on the second chromosome, the region of the second chromosome translocated onto the W chromosome was also defined. In both the A95 and A 96 strains selected for the present study, only the mid-portion of the second chromosome was translocated. The differences in length of the fragments translocated in these strains are discussed.

【 授权许可】

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