We newly isolated seven W chromosome derived bacterial artificial chromosome (W-BAC) clones from
Bombyx mori BAC libraries by means of six different STS primer sets, which amplify each different female specific DNA fragment. Two color fluorescence
in situ hybridization (FISH) with 19L6H W-BAC probe as a standard W-chromosome painter disclosed that six out of seven new W-BAC probes strongly highlighted the whole W chromosome in
B. mori. Besides the W, hybridization signals occurred in telomeric and/or subtelomeric regions of the autosomes. The remaining W-BAC, 20H9D, provided discontinuous signals, which appeared in both terminal and central compartments of the W chromosome. A representative of W-chromosome painting BACs, 19L6H, and 20H9D W-BAC were hybridized to chromosome spreads of
Bombyx mandarina females. The 19L6H W-BAC bound to the whole
B. mandarina W chromosome as in
B. mori. In contrast, 20H9D W-BAC signals in
B. mandarina W chromosome were different from those in
B. mori W, indicating rearrangements of the W chromosome during karyotype evolution of the two closely related
Bombyx species. Further FISH analyses using
B. mori W-BAC probes in 15 lepidopteran species showed no hybridization signals in their sex chromosomes as well as autosomes. Our results suggest the absence of homologous sequences between the
Bombyx W and the W chromosomes of other lepidopteran species.
抄録全体を表示