低温诱发嵌合体蚕的真皮细胞的性染色质小体

研究调查了低温处理受精卵诱发的斑纹嵌合体蚕的真皮细胞的性染色质小体（ＳＢ）。（１）限性淡灰色斑蚕品种的斑纹嵌合体幼虫的淡灰色斑部位的真皮细胞均存在ＳＢ，而素斑或普通斑部位的真皮细胞都不存在ＳＢ，表现为体细胞雌雄嵌合体。同一个体内，ＳＢ仅存在于持有Ｗ染色体的细胞中，不受嵌合体幼虫生殖腺性别的影响。（２）非限性斑蚕嵌合体幼虫有两种：正常受精部分与单性生殖部分组成的嵌合体，其雌核发生部位真皮细胞的ＳＢ存在状况与受精核发生部位相当一致；雄核发生部位则不存在ＳＢ。由两个正常受精部分组成的嵌合体，其各斑纹部位真皮细胞的ＳＢ的存在状况几乎完全一致。（３）认为第二极体是嵌合体蚕形成时雌核发生部分的主要参与者。

SEX CHROMATN IN THE EPIDERMAL NUCLEI OF THE COLD TREATMENT INDUCED MOSAICLARVAE OF THE SIKWORM Bombyx mori

The sex chromatin body(SB)in the epidermal nuclei on each side of the markingmosaic larvae of the silkworm Bombyx mori induced by cold treatment(90 180 minutesold eggs were treated at 5℃ for 24 hr.)and the histogenesis were investigated.1)TheSBs were observed in the epidermal nuclei of the sable part of the sex limited sablemarking mosaic,no SB was detected in those of the normal or plain part.The non sex limited marking mosaic larvae were mosaiced by a part developed from a fertilized eggnucleus and a part from female or male parthenogenesis,or by two parts developed fromtwo fertilized egg nuclei individually.2)The majority of the existence of SBs on the fe-male parthenogenetic side were in agreement with the fertilized side(67 100%),and noSB was detected in nuclei on the androgenca side.When the larvae were mosaiced by twodifferent fertilized parts,the SB existence of one side was almost similar to another(99.3)These results indicated that the female parthenogenetic side of the inducedmosaics is mainly developed from the fused nucleus of the second polar body and one ofthe first polar bodies or from the second polar body only.