An X/Y DNA segment from an early stage of sex chromosome differentiation in the fly Megaselia scalaris.
The sex chromosomes of the Megaselia scalaris wild-type strain Wien are homomorphic. We studied a roughly 1.8 kb X/Y DNA segment of this strain. It includes, at one end, the first part of a coding sequence for a protein of the vespid antigen 5 family. Molecular differentiation between the X and Y chromosomes has commenced, but homology, even of short DNA stretches, is still assessable beyond doubt. The most conspicuous differences between the X and the homologous Y segment were insertions/deletions in the noncoding region: among them, deletions, a duplication, and an insertion of a mobile element. These structural changes grossly disrupted homology. In comparison, base substitutions, though more numerous, contributed little to the differentiation of the X/Y DNA segment.
Traut
W
W
Institut für Biologie, Medizinische Universität zu Lübeck, Germany. traut@molbio.mu-luebeck.de
Wollert
B
B
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002874:Chromosome Mapping; D004175:Diptera / Q000235:genetics*; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012150:Polymorphism, Restriction Fragment Length; D016415:Sequence Alignment; D019849:Sex Determination Processes; D014960:X Chromosome; D014998:Y Chromosome