家蚕幼虫真皮细胞及生毛细胞的性染色质小体

本实验观察了家蚕真皮细胞核和生毛细胞核的性染色质小体(sex-chromatin body,以下简称SB)的存在情况,得出如下结果。 (1)雌蚕的真皮细胞核从4龄起,生毛细胞核从3龄起可以很明显的观察到SB。观察SB的最好时期是5龄期。(2)在正常个体中,真皮细胞核的SB数与生毛细胞核的SB数总是相同的。二倍体雌蚕的每个核中存在有1个SB,而四倍体雌蚕的每个核中存在有2个SB。(3)雄蚕的细胞核中不存在SB。 根据上述结果,讨论了SB在各龄期的变化及其与真皮细胞和生毛细胞成长的关系;讨论了SB与W染色体的等同关系。

THE SEX-CHROMATIN IN NUCLEI OF THE EPIDERMIS AND TRICHOGEN OF THE SILKWORM LARVA, Bombyx mori

The behavior of the sex-chromatin body (SB) in the nuclei of the epidermis and trichogen in the larval segment and the relationship between the SB and W chromosome (sex chromosome for female determination) was investigated. 1) The SB was clearly observed in the nucleus of the epidermis in the larva from the 4th to the 5th instar and of the trichogen in the larva from the 3rd to the 5th instar, but it was very difficult to find the SB in the epidermis untill the end of the 3rd instar and in the trichogen before the end of the 2nd instar larva. In both cases, the best stage for observing SB was the 5th instar. 2 ) The number of SBs per nucleus in the epidermis was equal to that of the tichogen in the same larva. 8) A single SB was observed per nucleus in the diploid female (the chromosome formula is 2A+ZW) , whereas two SBs were observed in the tetra-ploid female (4A + ZZWW) .There was no SB detected in the nuclei of the male (2A+ZZ or 4A + ZZZZ) .Based on these results, it was suggested that the SB in the nuclei of the epidermis and trichogen corresponded to the W chromosome as it was in the case of other tissues of the larva and adult moth.