| First Author | Davisson MT | Year | 1988 |
| Journal | Mouse News Lett | Volume | 80 |
| Pages | 166 | Mgi Jnum | J:23094 |
| Mgi Id | MGI:70889 | Citation | Davisson MT (1988) New chromosome aberrations. Mouse News Lett 80:166 |
| abstractText | Full text of MNL contribution: Research News. 2. New Chromosome aberrations. Two new paracentric inversions have been induced during a project to produce translocations in the mouse. Both inversions were identified in progeny of irradiated (1000R gamma radiation, cesium source) DBA/2J males x C57BL/6J females. Cytological breakpoints of In(4)lDn are in G-bands 4C2 and 4D3. In the small sample tested so far the inversion appears not to recombine with the brown locus (0/6). The lack of recombination between brown and a chromosome breakpoint in this region is consistent with our previous observation that T(3D;4B3)5Rk does not recombine with brown. Although InlDn involves nearly half of Chr 4 cytologically, the frequency of anaphase bridges in heterozygous males is not significantly different from that in +/+ sibling controls. Preliminary synaptonemal complex analysis suggests that inversion loops rarely form in heterozygotes. In(11)2Dn has cytological breakpoints in G-bands 11A4 and distal 11B1. In2Dn heterozygous males also do not have an anaphase bridge frequency different from +/+ littermates, but this inversion involves only about one fifth of Chr 11. Female and male heterozygotes for either inversion are fertile. I thank Norman L. Hawes for doing the anaphase bridge counts in these mice. A new Robertsonian chromosome, Rb(6.18)2Dn was identified in the same study. The Robertsonian was not induced by irradiation since it was present in the C57BL/6J parent. It apparently arose spontaneously in this mouse or a recent ancestor in The Jackson Laboratory Animal Resources C57BL/6J expansion colony. Subsequent screening of all retired breeders from The Jackson Laboratory's Foundation Stocks C57BL/6J colony has shown that Rb2Dn is not present in the main Jackson Laboratory C57BL/6J colony. (Davisson) |
