| First Author | Evans EP | Year | 1987 |
| Journal | Mouse News Lett | Volume | 77 |
| Pages | 147 | Mgi Jnum | J:14119 |
| Mgi Id | MGI:62295 | Citation | Evans EP, et al. (1987) A repositioning of the X Chromosome breakpoint of T(X;11)38H. Mouse News Lett 77:147 |
| abstractText | Full text of MNL contribution: A repositioning of the X chromosome breakpoint of T(X;11)38H. In two previous publications (MNL 57:17 and Searle et al., 1983, Cytogenet. Cell Genet. 35: 279-292) the breakpoints of both T(X;4)37H and T(X;ll)38H were described as being in XA2. A recent study (Lyon et al., 1986, J. Embryol. Exp. Morph. 97; 75-85), however, has shown conclusively that whereas the T37H breakpoint was correctly determined as being proximal in XA2, the T38H breakpoint is in XA1 which is synonymous with the C band. Evidence for the repositioning comes from two sources. 1) In G banded preparations some of the XA1 band material was observed on the 1lX long marker but not on the 4x long marker. 2) By in situ hybridisation, the locus of ornithine carbamoyltransferase (Otc) was shown to be distal to the breakpoint in T38H (on the long llx) but proximal in T37H (on the short x4), a finding which confirms previous observations that the small marker of T38H, in being smaller than that of T37H, contains less X chromosome material. The positioning of a locus in the A1 or C band composed largely of centromeric heterochromatin would appear to be unacceptable but recent higher resolution studies in this laboratory (see also, Sawyer and Hozier, 1986, Science 232: 1632-1635) reveal that the apparently uniformly dark staining XA1 band can be differentiated into three sub-bands. These include a pale staining band, in which Otc may be located. (Evans, Burtenshaw and M.F. Lyon) |
