The sex-ratio in the normal lines of Drosophila obscura is very near to the theoretical 1:1.
Out of 19 females caught in nature, two were heterozygous for a gene which causes strong deviations in the normal sex distribution.
The researches made have shown that this gene is localized in the X-chromosome and is transmitted like an ordinary sex-linked gene.
This gene is absolutely sex-limited, as it is not manifested either in heterozygous or homozygous females.
The males bearing this gene give in their progeny about 96 percent of females and only about 4 percent of males.
This gene has no influence on the development of the zygotes already formed, but acts directly upon the mechanism of sex-distribution. It provokes a sharp preponderance of females by almost totally removing the spermatozoa with the Y-chromosome from the fertilization process, acting thus like a gametic lethal (in the genetic sense of this term).
https://www.geneconvenevi.org/wp-content/uploads/2020/04/Genetics-77.png300300David Obrochtahttps://www.geneconvenevi.org/wp-content/uploads/2024/08/fnih-rm-mid.pngDavid Obrochta1928-12-30 21:32:102020-04-22 16:56:23A new sex-ratio abnormality in Drosophila obscura
