Characterizing a lethal mitonuclear incompatibility in naturally hybridizing Xiphophorus swordtails

This project described a mitonuclear incompatibility in naturally hybridizing swordtail fish. Lab-bred and natural hybrids were used for admixture mapping, revealing selection on interspecific combinations of mitochondrial and nuclear loci. Embryos were sequenced to show that individuals with specific mismatched protein combinations fail to complete embryonic development, while a set of seven hybrids heterozygous for the incompatibility were used to test for reduced physiological function of respiratory Complex I. Whole genome sequences from X. malinche and X. pygmaeus were used in phylogenetic analyses, and mitochondrial amplicons were used to estimate within- and between-species diversity.