The T6 translocation in the mouse: its use in trisomy mapping, centromere localization, and cytological identification of linkage group 3

Abstract

The occurrence of hairless piebald mice trisomic for the chromosome segments of the T6M chromosome has shown that the LG III loci hr and s are not located on T6M. The T6 breakpoint in LG III is therefore in the position hr-s-T6. T6M must carry the gene Fkl, which is located on the far side of the T6 breakpoint from hr in LG III.-T6 reduces recombination in the hr-s region.-Trisomy for the chromosome segments of the T6M chromosome appears to severely reduce viability.-The gene hr has been shown to lie between the centromere and the T6 breakpoint. The order of loci in LG III is therefore: centromere-hr-s-T6.-Equations are given for the relation between the frequency of adjacent-2 segregation and the frequency of recovery of complementation zygotes for the case in which the translocation heterozygote can form either quadrivalent or univalent-trivalent configurations at meiosis.-Linkage Group III is carried on chromosome 14. LG VI is the other linkage group involved in T6, and is carried on chromosome 15.