P. L. PEARSON and M. BOBROW
J. P. M. GERAEDTS and P. L. PEARSON
The positions of chromosomes 1 and Y inside human spermatozoa were determined by differential staining techniques. In 85/100 cells the two chromosomes were in close contact and in association with a vacuole. This observation is in contrast to previous findings for chromosome No. 9 and the Y-chromosome whose positions do not appear to be correlated.
A. D. TATES, P. L. PEARSON and J. P. M. GERAEDTS
Department of Radiation Genetics and Chemical Mutagenesis, and Department of Human Genetics, Medical Faculty, University of Leiden, The Netherlands
(Received 9th August 1974)
The introduction of a quinacrine staining technique for identifying human chromosomes (Zech, 1969) also permitted recognition of the human Y chromosome in non-dividing cells (Pearson, Bobrow & Vosa, 1970), including spermatozoa (Pearson & Bobrow, 1970; Barlow & Vosa, 1970). The ability to distinguish between human X- and Y-bearing spermatozoa has been used in estimating the difference in the DNA content of these spermatozoa (Sumner, Robinson & Evans, 1971; Pearson, Geraedts & Pawlowitzki, 1973), the primary non-disjunctional frequency of the Y chromosome (Sumner, Robinson & Evans, 1971; Pawlowitzki & Pearson, 1972) and, more recently, for judging the success of a separation technique for X and Y spermatozoa (Ericsson, Langevin & Nishino, 1973). Chromosomes 1 and 9 have also been recognized in human spermatozoa (Pearson, 1972; Bobrow, Madan &