A Test of Double Interspecific Introgression of Nucleoporin Genes in Drosophila

Abstract In interspecific hybrids between Drosophila melanogaster and Drosophila simulans, the D. simulans nucleoporin-encoding Nup96sim and Nup160sim can cause recessive lethality if the hybrid does not also inherit the D. simulans X chromosome. In addition, Nup160sim leads to recessive female sterility in the D. melanogaster genetic background. Here, we conducted carefully controlled crosses to better understand the relationship between Nup96sim and Nup160sim. Nup96sim did not lead to female sterility in the D. melanogaster genetic background, and double introgression of Nup96sim and Nup160sim did not generally lead to lethality when one was heterozygous and the other homozygous (hemizygous). It appears that introgression of additional autosomal D. simulans genes is necessary to cause lethality and that the effect of the introgression is dominant to D. melanogaster alleles. Interestingly, the genetic background affected dominance of Nup96sim, and double introgression carrying homozygous Nup96sim and hemizygous Nup160sim resulted in lethality. Thus, Nup96sim and Nup160sim seem to be two components of the same incompatibility.