Natural hybridization reveals incompatible alleles that cause melanoma in swordtail fish

• DOI: 10.1126/science.aba5216
• Publication Date: 2020-05-14T23:09:47Z
• Authors: Daniel L. Powell; Mateo García-Olaz...; Mackenzie Keegan; Patrick Reilly; Kang Du; Alejandra P. Díaz...; Shreya Banerjee; Danielle Blakkan; David Reich; Peter Andolfatto; Gil G. Rosenthal; Manfred Schartl; Molly Schumer
• Keywords: Fish Proteins; 0301 basic medicine; 0303 health sciences; Chimera; Receptor Protein-Tyrosine Kinases; Cyprinodontiformes; Fish Diseases; 03 medical and health sciences; Genetic Loci; Animal Fins; Animals; Hybridization, Genetic; 14. Life underwater; Melanoma; Alleles; Genome-Wide Association Study

Mapping vertebrate incompatibility alleles

Deleterious gene interactions may underlie the observed hybrid incompatibilities. However, few genes underlying hybrid incompatibilities have been identified, and most of these involve species that do not hybridize in natural conditions. Powell et al. used genome sequencing to map genes likely responsible for incompatibilities that reduce fitness in naturally occurring hybrid swordtail fish. These gene combinations result in malignant melanoma, which is found in naturally hybridizing populations but is not present in the parental populations (see the Perspective by Dagilis and Matute). Using genome and population resequencing, the authors performed a genome-wide association study to identify potentially causative mutations. Using an admixture mapping approach that assessed introgression between multiple swordtail fish species, the authors suggest that lineages carry different genes that interact with the same candidate gene, resulting in the observed melanomas and providing insight into convergent hybrid incompatibles that arise between species.

Science , this issue p. 731 ; see also p. 710