Multiple Allelism of the net Gene in Drosophila melanogaster and Drosophila simulans

Abstract

The net gene mutations are known to cause abnormal pattern of veining in all wing regions except for the first posterior cells. In natural populations of Drosophila melanogaster, the net alleles were identified, which differ in phenotypic expression from standard mutations. The mutants net-extra-analis from a population Belokurikha-2000 have only a single additional vein in the third posterior cell. A line from Chernobyl-1986 population have another nontypical allele netCh86 and shows a lower degree of abnormalities than that usually observed. About 10% of these flies have an additional vein fragment in the first posterior cell. In both males and females of D. simulans population Tashkent-2001, which exhibit netST91 mutation, a net of additional veins is formed as a specific additional fragment in the first posterior cell. The pattern of veining conferred by alleles net-extra-analis and netCh86 is altered to a lesser extent; these alleles are dominant with respect to alleles net2-45 and netST91, which cause more abnormalities. The heterozygotes for alleles netST9 and netCh86 and for Df(2) net62 deletion have an additional fragment in the first posterior cell and show similarly strong deviations from normal wing vein pattern. The natural net alleles correspond, presumably, to different molecular gene defects involved into uncertain local interactions with numerous modifying factors and other genes that specify the wing vein pattern.