Alpaca coat color is a relevant feature both for breeders than textile industries. Agouti (ASP) and Extension (MC1R) are genes known to be involved in coat color through pigmentation pathways by regulating type, amount and distribution of eumelanin and pheomelanin pigments in melanocytes. In alpaca genotype of ASP and MC1R genes have already been analysed distinctly, but their epistatic interaction have not been evaluated. In this study, in black animals, MC1R is epistatic over ASP : recessive alleles in Agouti (a) and dominant allele in Extension locus (E) produces black phenotype (aH/aΔ57 and aH/ahT genotype on Agouti and E/E or E/e genotype on MC1R locus). Otherwise ASP and MC1R in Brown animals have a no epistatic interaction : both genes presents at least one dominant (wild) allele : A/A, A/ahT on Agouti and E/e on Extension. Segregation analysis of 12 alpaca genotyped families for ASP and MC1R, confirm the dominance of brown.
Two different phenotypes are described in alpaca for type of fleece, suri and huacaya. In our study, the Fibroblast growth factor 5 (FGF5) was investigated as a possible candidate gene for hair length in alpaca. As previously identified in other mammals, our results show that the alpaca FGF5 gene gives rise to a short (FGF5S) and a long (FGF5) isoform. Interestingly, in the long isoform, we observed a point mutation (i.e., a transition C > T at position 499 downstream of the ATG codon) that is able to generate a premature termination codon (PTC). The highly conserved nucleotide and amino acid sequence after PTC suggested a readthrough event (RT) that was confirmed by western blot analysis. The analysis of cDNA sequence revealed motifs and structures of mRNA undergoing RT. In fact, the event is positively influenced by particular signals harbored by the transcript. To the best of our knowledge, this is the first case of a readthrough event on PTC reported for the FGF5 gene and the first case of this translational mechanism in alpaca.
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