Genetic mapping of Z chromosome and identification of W chromosome-specific markers in the silkworm, Bombyx mori

Heredity (Edinb). 2005 Aug;95(2):148-57. doi: 10.1038/sj.hdy.6800700.

Abstract

In the silkworm, Bombyx mori, the female is the heterogametic (ZW) sex and the male is homogametic (ZZ). The female heterogamety is a typical situation in the insect order Lepidoptera. Although the W chromosome in silkworm is strongly female determining, no W-linked gene for a morphological character has been found on it. The Z chromosome carries important traits of economic value as well as genes for various phenotypic traits, but only 2% of molecular information based on its relative size is known. Studies conducted so far indicate that the Z-linked genes are not dosage compensated. In the present study, we constructed a genetic map of randomly amplified polymorphic DNA fragments (RAPD), simple sequence repeats (SSR), and fluorescent intersimple sequence repeat PCR (FISSR) markers for the Z chromosome using a backcross mapping population. A total of 16 Z-linked markers were identified, characterized, and mapped using od, a recessive trait for translucent skin as an anchor marker yielding a total recombination map of 334.5 cM. The linkage distances obtained suggested that the markers were distributed throughout the Z chromosome. Four RAPD and four SSR markers that were linked to W chromosome were also identified. The proposed mapping approach should be useful to identify and map sex-linked traits in the silkworm. The economic and evolutionary significance of Z- and W-linked genes in silkworm, in particular, and lepidopterans, in general, is discussed.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Bombyx / genetics*
  • Chromosome Mapping
  • Female
  • Genetic Markers
  • Male
  • Minisatellite Repeats
  • Molecular Sequence Data
  • Physical Chromosome Mapping / methods*
  • Random Amplified Polymorphic DNA Technique
  • Sex Chromosomes / genetics*

Substances

  • Genetic Markers