An XXY mouse, the result of a rearrangement between one X and a Y chromosome.
A male mouse with irregular white spotting, typical of piebald, s, arose during an experiment designed to search for mutations induced in spermatogonial cells by ethylnitrosourea (ENU). On being examined cytologically it was found to carry 40 chromosomes but was effectively XXY since one of the two X chromosomes present was distally fused to a Y chromosome. In common with the previously described XXY mice, all of which carried 41 chromosomes, the mouse was sterile with a total absence of germ cells. Because of this, it was not possible to determine if the white spotting was inherited. The spotting could not be related to any observable abnormality of chromosomes known to carry spotting genes, nor could it be linked in any way with the X and Y fusion. It was concluded from the cytological considerations and the time interval (6 months) that had elapsed between mutagen treatment and birth of the offspring, that whereas the spotting was probably the result of ENU damage in a spermatogonial stem cell, the XY fusion was probably a later and spontaneous event.
Evans
E P
EP
Sir William Dunn School of Pathology, University of Oxford, UK.
Breckon
G
G
Peters
J
J
D000818:Animals; D015321:Gene Rearrangement; D007248:Infertility, Male / Q000235:genetics; D007621:Karyotyping; D008297:Male; D051379:Mice; D012729:Sex Chromosome Aberrations / Q000235:genetics*