Patterns of replication in the neo-sex chromosomes of Drosophila nasuta albomicans.
Drosophila nasuta albomicans (with 2n = 6), contains a pair of metacentric neo-sex chromosomes. Phylogenetically these are products of centric fusion between ancestral sex (X, Y) chromosomes and an autosome (chromosome 3). The polytene chromosome complement of males with a neo-X- and neo-Y-chromosomes has revealed asynchrony in replication between the two arms of the neo-sex chromosomes. The arm which represents the ancestral X-chromosome is faster replicating than the arm which represents ancestral autosome. The latter arm of the neo-sex chromosome is synchronous with other autosomes of the complement. We conclude that one arm of the neo-X/Y is still mimicking the features of an autosome while the other arm has the features of a classical X/Y-chromosome. This X-autosome translocation differs from the other evolutionary X-autosome translocations known in certain species of Drosophila.
Mahesh
G
G
Drosophila Stock Centre, Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka, India.
Ramachandra
N B
NB
Ranganath
H A
HA
D000818:Animals; D002875:Chromosomes / Q000502:physiology* / Q000648:ultrastructure; D004261:DNA Replication; D004330:Drosophila / Q000235:genetics* / Q000254:growth & development; D019143:Evolution, Molecular; D007814:Larva; D010802:Phylogeny; D012469:Salivary Glands / Q000648:ultrastructure; D012730:Sex Chromosomes / Q000502:physiology / Q000648:ultrastructure; D014178:Translocation, Genetic