Meiotic behavior of asymmetric dyads in the male Drosophila.

Crossing over in the interstitial region of the heterozygous V(4) translocation in Drosophila melanogaster generates asymmetric dyads each consisting of a shorter and a longer chromatid. It was shown previously that in the female the shorter is recovered preferentially (Zimmering 1955); the present work suggests that the same occurs in the male as well. The mechanism in the female is envisioned as involving the non-random inclusion of the shorter chromatid into the functional egg (Novitski 1951); in the male, the two formal possibilities appear to be (1) that some proportion of sperm carrying the longer chromatid derived from an asymmetric dyad undergoes dysfunction, or (2) the longer chromatid is preferentially included into regularly-produced nonfunctional sperm, the nonfunctionality set up at the second division and distinguishing second division daughter cells.