Chromosome banding in podisma pedestris

Abstract

C-banding of P. pedestris chromosomes demonstrated the presence of small procentromeric heterochromatic blocks on all members of the complement. The telocentric X-chromosomes and all of the medium sized autosomes also had small distally located C-bands and the megarmeric M7 chromosome consistently had a number of interstitial bands. The metacentric neo X chromosome found in some populations has a distinctive C-banding pattern in that although the distal C-block of the free X is retained, the centromeric heterochromatin is quite asymetrical with most of the procentric C-band of the X apparently having been lost during or subsequent to the X-autosome fusion event. Two banding polymorphisms were noted, an extra C-band on the S10 chromosome and variability in size of the distal C-band on the M6. B-chromosomes did not appear to have any C-band material other than a small procentric block. G-banding gave no additional information as the chromosomes appeared light staining only in those regions which were C-positive. Use of the fluorochromes Hoechst 33258 and Chromomycin A3 showed that the heterochomatin of P. pedestris is relatively rich in G + C bases. © 1985 The Genetical Society of Great Britain.