ISSN:
1573-6849
Keywords:
sex chromosome evolution
;
dosage compensation
;
Drosophila
;
histone acetylation
;
X chromosome
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract In polytene chromosome squashes from the fruit flyDrosophila melanogaster, the single, dosage-compensated X chromosome in males can be distinguished from the autosomes by the presence of an isoform of histone H4 acetylated at lysine 16, H4.Ac16. We have used H4.Ac16 as a marker to examine the evolving relationship between dosage compensation and sex chromosome composition in species ofDrosophila with one (D. melanogaster), two (D. pseudoobscura) or three (D. miranda) identifiable X chromosome arms. In each case, we find that H4.Ac16 is distributed as discrete, closely spaced bands along the entire length of each X chromosome, the only exception being the X2 chromosome ofD. miranda in which a terminal region constituting about 10% of the chromosome by length is not labelled with anti-H4.Ac16 antibodies. We conclude that, with this exception, dosage compensation extends along the X chromosomes of all three species. AsD. pseudoobscura andD. miranda diverged only about 2 Mya, the spread of dosage-compensated loci along X2 has been rapid, suggesting that regional changes rather than piecemeal, gene-by-gene, changes may have been involved.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02254957
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