Yokoyama Takeshi, Abe Hiroaki, Irobe Yasuo, Saito Katsuji, Tanaka Nobuhiko, Kawai Shinya, Ohbayashi Fumi, Shimada Toru, Oshiki Toshikazu
Department of Biological Production, Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, Japan.
Hereditas. 2003;138(2):148-53. doi: 10.1034/j.1601-5223.2003.01720.x.
The sex chromosomes of the silkworm, Bombyx mori, are designated ZW for the female and ZZ for the male. We previously characterized a female-specific randomly amplified polymorphic DNA (RAPD) marker, designated Female-218, from the translocation-bearing W chromosomes. These W chromosomes contain a region of the second chromosome, which carries visible larval markers of the p loci. We used strain TWPB in which female larvae have black skin due to the p(B) gene (T(W;2)p(B), +p/+p) while male larvae have whitish skin (+p/+p). To determine whether the Female-218 RAPD marker is derived from the "W region" or a "second chromosome fragment", we induced a detachment of the translocated W chromosome, T(W;2)p(B), by treating the eggs with hot water at an early developmental stage. After hot water treatment, we obtained 27 white female larvae out of 4850 female larvae. The Female-218 RAPD marker was not amplified in 26 out of 27 white female larvae, and was amplified from one white female larva. Moreover, we obtained 11 black male larvae out of 5377 male larvae. Eight out of 11 black male larvae became adult moths, and the Female-218 RAPD marker was amplified from all eight male moths. Examination of the genetic relationship between the Female-218 RAPD marker and the second chromosome fragment of the translocated W chromosome strongly indicates that the Female-218 RAPD marker is amplified from the region of second chromosome fragment of the T(W;2)p(B) chromosome.
家蚕的性染色体，雌性为ZW，雄性为ZZ。我们之前从携带易位的W染色体中鉴定出一个雌性特异性随机扩增多态性DNA（RAPD）标记，命名为Female - 218。这些W染色体包含第二条染色体的一个区域，该区域携带p位点的可见幼虫标记。我们使用了TWPB品系，其中由于p(B)基因（T(W;2)p(B), +p/+p），雌性幼虫有黑色皮肤，而雄性幼虫有白色皮肤（+p/+p）。为了确定Female - 218 RAPD标记是来自“W区域”还是“第二条染色体片段”，我们在发育早期用热水处理卵，诱导易位的W染色体T(W;2)p(B)分离。热水处理后，在4850只雌性幼虫中我们获得了27只白色雌性幼虫。27只白色雌性幼虫中有26只未扩增出Female - 218 RAPD标记，只有一只白色雌性幼虫扩增出该标记。此外，在5377只雄性幼虫中我们获得了11只黑色雄性幼虫。11只黑色雄性幼虫中有8只发育成成虫蛾，并且所有8只雄性蛾都扩增出了Female - 218 RAPD标记。对Female - 218 RAPD标记与易位W染色体的第二条染色体片段之间遗传关系的研究有力地表明，Female - 218 RAPD标记是从T(W;2)p(B)染色体的第二条染色体片段区域扩增而来的。
