Interchange between X- and Y-Chromosomes in Attached X Females of Drosophila Melanogaster

Abstract

Detached X-chromosomes from XXY [female][female] are of 2 types, V-shaped or J-shaped, which seem to occur with about equal frequency. The former is interpreted as a compound consisting of a rod-shaped X-chromosome and the long arm of the Y-chromosome (the XYL-chromosome). The J-shaped chromosome is regarded as a compound of the X and the short arm of the Y (the XYs-chromosome, a type of compounding of X and Y previously undescribed). It is suggested that detachment occurs as a result of exchange between X- and Y-chromosomes. It could not be determined cytologically whether the exchange occurs between the long arm of the Y and the proximal region of the X, or between the short arm of the Y and the proximal region of the X. Other factors suggest that the short arm of the Y is usually involved.