Genetic Variation in an Experimental Goldfish Derived From Hybridization

Area of Science:

• Genetics
• Evolutionary Biology
• Aquaculture

Background:

• The common ancestor of twin-tail goldfish remains unidentified due to challenges in tracing the primary generation (G0).
• Crucian carp (Carassius auratus) has been hypothesized as a potential ancestor for goldfish strains.
• Experimental hybrid goldfish (EG) were previously created from red crucian carp (RCC) and common carp (CC).

Purpose of the Study:

• To investigate the genetic characteristics of experimental hybrid goldfish (EG) and the mechanisms behind its twin-tail phenotype.
• To explore the genetic variation associated with the twin-tail trait in EG.
• To shed light on the common ancestor of natural goldfish (NG) and the role of hybridization in NG speciation.

Main Methods:

• Identified genetic variation in the chordin gene within the experimental hybrid goldfish (EG).
• Analyzed the chordin gene for mutations, specifically a stop codon at the 127th amino acid.
• Utilized simple sequence repeat (SSR) genotyping to compare alleles between EG, its parents (RCC and CC), and natural goldfish (NG).

Main Results:

• A stop codon mutation in the chordin gene at the 127th amino acid was identified and linked to the twin-tail phenotype in EG.
• SSR genotyping revealed that all EG alleles were present in the female parent (RCC), with complete loss of male parent (CC) specific alleles.
• Allelic differences were observed between EG and NG at some loci, indicating genetic dissimilarities between morphologically similar goldfish.

Conclusions:

• Genetic variations and differentiation play a crucial role in the morphological changes observed in hybrid offspring.
• The study provides new perspectives on the common ancestor of natural goldfish (NG).
• Hybridization and artificial breeding are significant factors in the speciation process of goldfish.