银额果蝇的B染色体研究:1.昆明群体的Bs数目和频率

The Study of B Chromosomes In Drosophila albomicans Ⅰ. The Number and Frequency of Bs In Kunming Population

摘要: 本研究发现银额果蝇昆明群体有丝分裂中期核型中存在B染色体，出现频率为69.1%。目前，在已研究过的来自各个地区的银额果蝇中，昆明群体的B染色体频率最高。B染色体数目为1-6条。该群体内单雌系间的B染色体数目不同，个体间和细胞间的B染色体数目也不同。在核型中，B染色体最小，形态稳定，点状，C-带和G-带呈阳性。

Abstract: In this study,mitotic metaphase of Drososphila albomicans with B-chromosomes were found in Kunming population.Their frequency of presence of B-chromosomes were 69.1%.At present,among D.albomicans has been studied from several localities,the frequency of B-chromosomes of Kunming population were the hightest.The number of B-chromosomes varied from 1 to 6 and differed between each iso-femals line of them as well as that of between individuals and cells.All the B-chromosomes were the smallest,dot-shaped of the karyotype.Both C-band and G-band staining are positive for B-chromosomes.