Chromosome constancy in the corneal epithelium of the mouse

Summary

A cell-to-cell variation in chromosome number (somatic inconstancy) is said to occur in some mammalian tissues. The polyploid element of this inconstancy appears to be well established, particularly for the liver, the blood, and in deciduomata. The reality of the aneuploid element has been disputed, and recent work has shown that the range and frequency of this variation must be considerably less than previously reported. The present work permits a positive statement about one mammalian tissue; in mitoses from the corneal epithelium of the mouse, constancy of chromosome number from cell to cell is virtually absolute. It is suggested that material for checking the existence of aneuploid inconstancy should be sought among differentiated tissues. The combination of technique and tissue used provides mitoses rivalling in clarity and abundance those obtainable from the testis, and may constitute a general method for assessing the diploid chromosome number of either sex in mammals. The centromere appears to be sub-terminal in most if not all of the chromosomes from the corneal epithelium of the mouse.