Identification of Candidate Genes for Red-Eyed (Albinism) Domestic Guppies Using Genomic and Transcriptomic Analyses

Area of Science:

• Genetics
• Animal Science
• Molecular Biology

Background:

• Domestic guppies exhibit two eye color phenotypes: red and black.
• The wild type guppy possesses black eyes.
• Understanding the genetic basis of eye color variation is crucial for selective breeding and fundamental research.

Purpose of the Study:

• To identify candidate genes responsible for the red-eyed phenotype in domestic guppies.
• To provide molecular genetic insights for developing novel domestic guppy strains.
• To contribute foundational knowledge to guppy genetics research.

Main Methods:

• Genome-wide association study (GWAS) on 121 domestic guppies.
• Transcriptomic analysis on 21 domestic guppies to identify differentially expressed genes (DEGs).
• Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis.
• Quantitative reverse transcription PCR (qRT-PCR) for validating candidate gene expression.

Main Results:

• GWAS identified 44 candidate genes.
• Transcriptomic analysis revealed 874 DEGs (357 upregulated, 517 downregulated).
• Enrichment analyses highlighted pathways related to melanin biosynthesis and ion transport.
• Expression of four key genes (TYR, OCA2, SLC45A2, SLC24A5) was verified, with OCA2 showing significant differential expression.

Conclusions:

• OCA2 is identified as the most significant candidate gene for the red-eyed phenotype in domestic guppies.
• The findings offer valuable genetic information for guppy breeding programs.
• This study enhances the understanding of genetic mechanisms underlying pigment variation in fish.