Temperature and “Sex-Ratio” in Drosophila Pseudoöbscura

Abstract

The "sex-ratio" gene or complex in the X-chromosomes of many Drosophila spp. causes the X-chromosome to divide twice at meiosis in the [male][male] while the Y is thrown out. This abnormality seems to depend on an excessive nucleic acid charge and should therefore (on other evidence) be affected by temp. This expectation was confirmed. The proportion of sperm was reduced from 99 to 94% by raising the temp. from 16[degree] to 25[degree]C.