Construction of chromosomal maps for silkworm, Bombyx mori using genetically mutants

1. 用风干法观察了家蚕不同减数分裂时期的染色体特征。减数分裂细胞的粗线后期到二倍体后期和体细胞的胚胎早期适合进行染色体的鉴定。对家蚕染色体突变体E^<Ds>进行了研究，该突变体在遗传学研究中被认为在6号和7号染色体之间有附着或易位。该突变体在中期I有27或28条染色体，在中期II有26、27、28、29和30条染色体。此外，卵的孵化率也很低。这些结果表明，E^<Ds>的畸变是由于连锁6和7.3之间的反向易位引起的。已知名为sol的基因属于第六个连锁群。涉及E和F基因的三点实验表明，sol位点确定为第6连锁群的-21.0位点。我们应用荧光原位杂交法重新评估这一结果。以Nc基因位点（第6连锁群1.4）的Bmantp序列为探针。在染色体的中间区域检测到信号，提示第6连锁群上的基因位点需要修改。

1. Chromosomal features at different meiotic stage in Bombyx mori were observed using air-dry method. The stage of late pachytene to diplotene in meiotic cell and the early embryonic stage in somatic cell are suitable for characterization of the chromosomes.2. The chromosomal mutant E^<Ds> of Bombyx mori, which was assumed by genetically studies to have attachment or translocation between chromosomes 6 and 7, was investigatelly. This mutant had 27 or 28 chromosomes at metaphase I and 26, 27, 28, 29 and 30 at metaphase II.In addition, the hatchability of egga was so much low. These results indicate that aberration of E^<Ds> is due to a reciprocal translocation between linkage 6 and 7.3. The gene named sol has been known to belong to the 6th linkage group. Three-point experiment involving E and F genes showed that the locus of sol was determined to be -21.0 of the 6th linkage group. We applied fluorescence in situ hybridization for reassessment of this result. Bmantp sequence of Nc gene locus (1.4 on 6th linkage group) was used as a probe. Signals were detected in the middle region of chromosomes, indicating that the gene loci on the 6th linkage group are to be revised.