Autoradiographic study of transcription and dosage compensation in the sex and neo-sex chromosome of Drosophila nasuta nasuta and Drosophila nasuta albomicans.
Cellular autoradiography is used to study the transcription patterns of the polytene X chromosomes in Drosophila nasuta nasuta and D. n. albomicans. D. n. nasuta, with 2n = 8, includes a pair of complete heteromorphic sex chromosomes, whereas D. n. albomicans, with 2n = 6, has a pair of metacentric neo-sex chromosomes representing incomplete heteromorphic sex chromosomes. The neo-X chromosome has two euchromatic arms, one representing the ancestral X while the other represents the ancestral autosome 3 chromosomes. The metacentric neo-Y chromosome has one arm with a complete heterochromatic ancestral Y and the other arm with a euchromatic ancestral autosome 3. The transcription study has revealed that the X chromosome in D. n. nasuta is hyperactive, suggesting complete dosage compensation, while in the neo-X chromosome of D. n. albomicans the ancestral X chromosome is hyperactive and the ancestral autosome 3, which is part of the neo-sex chromosome, is similar to any other autosomes. This finding shows dosage compensation on one arm (XLx/-) of the neo-X chromosome, while the other arm (XR3/YR3) is not dosage compensated and has yet to acquire the dosage compensatory mechanism.
Drosophila Stock Centre, Department of Studies in Zoology, University of Mysore, Manasagangotri, India.
G
G
Mahesh
N B
NB
Ramachandra
H A
HA
Ranganath
D000818:Animals; D001345:Autoradiography; D004303:Dosage Compensation, Genetic; D004330:Drosophila / Q000235:genetics*; D005260:Female; D008297:Male; D012737:Sex Factors; D013045:Species Specificity; D014158:Transcription, Genetic; D014960:X Chromosome; D014998:Y Chromosome