Table 1. Speciation genes causing postzygotic reproductive isolation that have been identified at the DNA sequence level.

Gene	Taxon	Hybrid phenotype	Gene type	Ref(s).
Xmrk-2	Xiphophorus	Inviability	Receptor tyrosine kinase	16-18
OdsH	Drosophila	Sterility	Transcription factor	22-24
Hmr	Drosophila	Inviability	Transcription factor	29, 30
Nup96	Drosophila	Inviability	Nucleoporin	34