In other species: chicken , Japanese quail

Categories: Pigmentation phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 609227 (trait) , 606526 (gene)

Links to relevant human diseases in MONDO:

• MONDO:0012220: Griscelli syndrome type 3

Mendelian trait/disorder: yes

Disease-related: no

Key variant known: yes

Year key variant first reported: 2023

Cross-species summary: Known as lavender feather colour

Species-specific description: Bovo et al. (2023): "exploited whole genome sequencing (WGS) datasets produced from five canary lines or populations (Black Frosted Yellow, Opal, Onyx, Opal × Onyx and Mogno, some of which carrying different putative dilute alleles), complemented with other WGS datasets retrieved from previous studies, to identify candidate genes that might explain pigmentation variability across canary breeds and varieties. ... We identified signatures of selection in genomic regions harbouring genes involved in carotenoid-derived pigmentation variants (CYP2J19, EDC, BCO2 and SCARB1), confirming the results reported by previous works, and identified several other signatures of selection in the correspondence of melanogenesis-related genes (AGRP, ASIP, DCT, EDNRB, KITLG, MITF, MLPH, SLC45A2, TYRP1 and ZEB2). Two putative causative mutations were identified in the MLPH gene that may explain the Opal and Onyx dilute mutant alleles."

Molecular basis: Bovo et al. (2023): "By investigating the MLPH gene sequence from the generated whole genome sequencing datasets, we identified two putative causative mutations of the dilute canary variants. A missense mutation (NW_022042652.1:g.66497548C>T; ... ), causing the p.R111K substitution at the protein level (XM_009088195.3; XP_009086443.1), was fixed in the Onyx canaries and had an estimated frequency of 0.58 in the Opal × Onyx DNA pool ... , close to the expected frequency of 50% based on fact that the crossbred canaries might have received a copy of the mutated allele from the Onyx parent and a wild-type form at this position from the other parental variety. ... The second mutation was a deletion of seven nucleotides (NW_022042652.1:g.66493407_66493413del; ...), causing a frameshift of the reading frame and then the constitution of a premature stop codon that truncates the 676 residue wild-type protein at residue 236 (p.A237fs; XP_009086443.1). This deletion was fixed in both Opal and Mogno canaries. Again, in the Opal × Onyx DNA pool, its frequency was close to the expected 1:1 ratio of the two parental alleles ... . This is again consistent with the fact that Opal and Onix carried two different MLPH alleles. As Opal and Mogno canaries carried the same allele at the MLPH gene, their phenotypic differences might be due to other modifier loci."

Associated gene: