Selection for winners impacts the endocrine system in the Siamese fighting fish.

Color morphs in ball pythons (Python regius) provide a unique and largely untapped resource for understanding the genetics of coloration in reptiles. Here we use a community-science approach to investigate the genetics of three color morphs affecting production of the pigment melanin. These morphs—Albino, Lavender Albino, and Ultramel—show a loss of melanin in the skin and eyes, ranging from severe (Albino) to moderate (Lavender Albino) to mild (Ultramel). To identify genetic variants causing each morph, we recruited shed skins of pet ball pythons via social media, extracted DNA from the skins, and searched for putative loss-of-function variants in homologs of genes controlling melanin production in other vertebrates. We report that the Albino morph is associated with missense and non-coding variants in the gene TYR. The Lavender Albino morph is associated with a deletion in the gene OCA2. The Ultramel morph is associated with a missense variant and a putative deletion in the gene TYRP1. Our study is one of the first to identify genetic variants associated with color morphs in ball pythons and shows that pet samples recruited from the community can provide a resource for genetic studies in this species.

https://www.biorxiv.org/content/biorxiv/early/2021/05/20/2021.05.19.444867.full.pdf

A community-science approach identifies genetic variants associated with three color morphs in ball pythons (Python regius)

https://onlinelibrary.wiley.com/doi/pdfdirect/10.1002/aff2.74

Pigmentary keratitis and mixed chromatophoroma in a betta fish (
 Betta splendens
 )

Siamese fighting fish, commonly known as betta, are among the world’s most popular and morphologically diverse pet fish, but the genetic processes leading to their domestication and phenotypic diversification are largely unknown. We assembled de novo the genome of a wild Betta splendens and whole-genome sequenced multiple individuals across five species within the B. splendens species complex, including wild populations and domesticated ornamental betta. Given our estimate of the mutation rate from pedigrees, our analyses suggest that betta were domesticated at least 1,000 years ago, centuries earlier than previously thought. Ornamental betta individuals have variable contributions from other Betta species and have also introgressed into wild populations of those species. We identify dmrt1 as the main sex determination gene in ornamental betta but not in wild B. splendens, and find evidence for recent directional selection at the X-allele of the locus. Furthermore, we find genes with signatures of recent, strong selection that have large effects on color in specific parts of the body, or the shape of individual fins, and are almost all unlinked. Our results demonstrate how simple genetic architectures paired with anatomical modularity can lead to vast phenotypic diversity generated during animal domestication, and set the stage for using betta as a modern system for evolutionary genetics. One-Sentence Summary Genomic analyses reveal betta fish were domesticated more than 1,000 years ago and the genes that changed in the process.

https://biorxiv.org/content/10.1101/2021.04.29.442030v1.full.pdf

Vranken N

Papers

Genomic consequences of domestication of the Siamese fighting fish