The Genetic Basis and Development of a Novel Tailspot Pattern in Xiphophorus variatus ...

Color polymorphisms are suggested to play a role in social and environmental adaptation, speciation, and potentially climate change response. Polymorphism, the appearance of two or more clearly different morphs within a population, is an example of the immense variation of life on earth. Swordtail and platyfish in the genus Xiphophorus possess a wide variety of polymorphic pigmentation traits. Of particular interest are the macromelanophore patterns, several of which are known to be involved in an extensively-studied hybrid incompatibility that causes melanoma in swordtail fish hybrids. The subject of this research is a trait we call the “confetti caudal,” a novel, previously unstudied macromelanophore polymorphism found in some populations of X. variatus. Here, I use a genome wide association study (GWAS) and tracking of lab born individuals to investigate the development and genetic basis of the trait. I find that the xmrk oncogene is a likely candidate for producing confetti caudal pigmentation. The size ...