A Loss-of-Function Mutation in bco1l Underlies Yellow Coloration in Large Yellow Croaker (Larimichthys crocea)

Area of Science:

• Aquaculture Genetics
• Fish Pigmentation
• Carotenoid Metabolism

Background:

• Carotenoid-derived coloration is crucial for the aesthetic and economic value of aquatic species.
• The large yellow croaker (Larimichthys crocea) is a significant aquaculture species in China, with coloration impacting its marketability.

Purpose of the Study:

• To identify the genetic underpinnings of yellow body coloration in the large yellow croaker.
• To explore the potential of identified genetic markers for aquaculture breeding programs.

Main Methods:

• Genome-wide association study (GWAS) to pinpoint genetic variations associated with yellow coloration.
• Sanger sequencing to validate the presence of the identified mutation in different color phenotypes.
• Functional assays using recombinant proteins to confirm the effect of the mutation on enzyme activity.

Main Results:

• A 10 bp deletion (bco1l-Δ10) in the bco1l gene was identified as the cause of yellow coloration.
• This mutation leads to a frameshift, premature stop codon, and loss of carotenoid cleavage function.
• The bco1l-Δ10 mutation was exclusively found in homozygous yellow juveniles, confirming its association with the phenotype.

Conclusions:

• The bco1l gene mutation is directly responsible for the yellow phenotype in large yellow croaker.
• The bco1l-Δ10 mutation serves as a valuable genetic marker for marker-assisted selection (MAS).
• MAS can be employed in breeding programs to enhance yellow pigmentation, potentially increasing the market value of L. crocea.