Carotenoids are essential compounds crucial for many biological processes, including vision, immune function, and antioxidant activity. Animals are unable to synthetise carotenoids de novo, relying entirely on their diet as a source. In animal tissues, β-carotene, a precursor of vitamin A, can accumulate, leading to yellow fat pigmentation. The metabolism of carotenoids is regulated by genes like SCARB1, BCO1 and BCO2. Mutations in these genes disrupt carotenoid breakdown, resulting in tissue accumulation and causing a yellow-fat phenotype observed in various species. In rabbit, a deletion of the AAT triplet at codon 248 of the BCO2 gene causes a recessive yellow-fat phenotype, which is expressed only in homozygous animals. Yellow-fat is considered a defect in meat production. This study aimed, for the first time, to investigate the presence and frequency of the BCO2 mutation in over 40 rabbit breeds and commercial lines. Genomic DNA was extracted from hair follicles from more than 500 rabbits, amplified by PCR, and Sanger sequenced. Genotyping revealed the mutation in both heterozygous and homozygous forms, with significant variation in allele frequency across breeds. Companion breeds showed a higher frequency of heterozygous rabbits, likely due to relaxed selection pressures and aesthetic preferences, while meat breeds exhibited lower frequencies, reflecting efforts to remove this genetic defect. The Lynx breed had the highest frequency of the mutated allele. This study highlights the widespread distribution of the BCO2 mutation in rabbits. Further studies should explore additional genetic factors affecting carotenoid metabolism in rabbits. The research was supported by the PSRN (Programma di Sviluppo Rurale Nazionale) Cun-Fu and Cun-Fu 2 projects (co-funded by the European Agricultural Fund for Rural Development of the European Union and by the Italian Ministry of Agriculture, Food Sovereign and Forestry (MASAF).
Taurisano, V., Ribani, A., Bovo, S., Schiavo, G., Bertolini, F., Schiavitto, M., et al. (2025). BCO2 allele frequencies in many rabbit breeds and populations: insights from the spread of a genetic defect [10.1080/1828051X.2025.2520034].
BCO2 allele frequencies in many rabbit breeds and populations: insights from the spread of a genetic defect
Valeria Taurisano;Anisa Ribani;Samuele Bovo;Giuseppina Schiavo;Francesca Bertolini;Luca Fontanesi
2025
Abstract
Carotenoids are essential compounds crucial for many biological processes, including vision, immune function, and antioxidant activity. Animals are unable to synthetise carotenoids de novo, relying entirely on their diet as a source. In animal tissues, β-carotene, a precursor of vitamin A, can accumulate, leading to yellow fat pigmentation. The metabolism of carotenoids is regulated by genes like SCARB1, BCO1 and BCO2. Mutations in these genes disrupt carotenoid breakdown, resulting in tissue accumulation and causing a yellow-fat phenotype observed in various species. In rabbit, a deletion of the AAT triplet at codon 248 of the BCO2 gene causes a recessive yellow-fat phenotype, which is expressed only in homozygous animals. Yellow-fat is considered a defect in meat production. This study aimed, for the first time, to investigate the presence and frequency of the BCO2 mutation in over 40 rabbit breeds and commercial lines. Genomic DNA was extracted from hair follicles from more than 500 rabbits, amplified by PCR, and Sanger sequenced. Genotyping revealed the mutation in both heterozygous and homozygous forms, with significant variation in allele frequency across breeds. Companion breeds showed a higher frequency of heterozygous rabbits, likely due to relaxed selection pressures and aesthetic preferences, while meat breeds exhibited lower frequencies, reflecting efforts to remove this genetic defect. The Lynx breed had the highest frequency of the mutated allele. This study highlights the widespread distribution of the BCO2 mutation in rabbits. Further studies should explore additional genetic factors affecting carotenoid metabolism in rabbits. The research was supported by the PSRN (Programma di Sviluppo Rurale Nazionale) Cun-Fu and Cun-Fu 2 projects (co-funded by the European Agricultural Fund for Rural Development of the European Union and by the Italian Ministry of Agriculture, Food Sovereign and Forestry (MASAF).I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
