title: Origin of X/O progeny from crosses of sex-ratio trait males of Drosophila pseudoobscura.
abstract: Males of Drosophila pseudoobscura carrying the sex-ratio chromosome (SR) were studied to determine the cause of X/O male progeny that they produce. It was found that among 3671 X/O progeny virtually all resulted from nullo-X sperm. The experiment also revealed a dramatic clustering of the frequency of X/O progeny among SR/Y males. This is interpreted to indicate that premeiotic events in the male germ line are the cause of nullo-X sperm.
mesh_terms: D000818:Animals; D003433:Crosses, Genetic; D004330:Drosophila / Q000235:genetics* / Q000502:physiology; D005260:Female; D008297:Male; D012744:Sex Ratio; D013094:Spermatozoa / Q000502:physiology; D014960:X Chromosome