On the origin of metacentric, attached-X (A-X) chromosomes in Drosophila melanogaster males.
We describe here the isolation and cytogenetic characterization of a mutation inseparabile which generates in males a high frequency of A-X females. The mutation, segregating in low frequency in a laboratory stock, maps to cytological location 82F7-11 in the third chromosome. The mutation acts premeiotically in the male germ line. Disrupting the X chromosome centromeric heterochromatin suppresses the formation of A-X chromosome, implying that the mutation is involved in chromatid cohesion. The inseparabile mutation also affects disjunction of the chromosome 4 in males. We suspect that the mutation was responsible for the original A-X female found by L. V. Morgan in 1921.
Green
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Section of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA.
Piergentili
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D000818:Animals; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D017344:Genes, Insect; D008040:Genetic Linkage; D008297:Male; D014960:X Chromosome