Katoh H, Ebukuro M, Suzuki H
Department of Genetics, Central Institute for Experimental Animals, Kawasaki, Japan.
Cytogenet Cell Genet. 1994;67(1):27-30. doi: 10.1159/000133719.
An inbred strain of mice has been identified that is homozygous for a chromosomal segment attached to the centromeric region of Chromosome (Chr) 5. The altered chromosome arose spontaneously, and it does not appear to interfere with fertility or to have a phenotypic effect. Karyotypic analysis based on G-banding and quinacrine/Hoechst-banding studies revealed a morphological similarity between the additional segment of Chr 5 and the centromeric region of Chr 12. The mutant strain possessed silver-stainable nucleolar organizer regions, not only in the centromeric regions of Chrs 12, 15, and 18 but also on the additional segment of Chr 5. We investigated the relationship between the additional segment and the restriction fragment length polymorphisms (RFLPs) for the variable region of ribosomal DNA and found a correlation between a HincII RFLP and either the abnormal Chr 5 or Chr 12. These results indicate that the origin of the additional segment was Chr 12 and that the segmental tetrasomy of the present strain is therefore due to a nondetrimental translocation between pericentromeric regions.
已鉴定出一种近交系小鼠，其与5号染色体（Chr）着丝粒区域相连的染色体片段是纯合的。这条改变的染色体是自发产生的，似乎不影响生育能力，也没有表型效应。基于G带和喹吖因/ Hoechst带研究的核型分析显示，5号染色体的附加片段与12号染色体的着丝粒区域在形态上相似。该突变株不仅在12号、15号和18号染色体的着丝粒区域具有银染核仁组织区，在5号染色体的附加片段上也有。我们研究了附加片段与核糖体DNA可变区的限制性片段长度多态性（RFLP）之间的关系，发现HincII RFLP与异常的5号染色体或12号染色体之间存在相关性。这些结果表明，附加片段的起源是12号染色体，因此本菌株的片段四体性是由于着丝粒周围区域之间的无害易位所致。
