Categories: Pigmentation phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 611539 (gene)

Single-gene trait/disorder: yes

Mode of inheritance: Autosomal dominant

Disease-related: no

Key variant known: no

Species summary: Goutte et al. (2025) "investigate the genetic architecture of GCP [green colour polymorphism] in a radiation of African grass frogs endemic to the Ethiopian Highlands (12 species; genus Ptychadena). Within this radiation, four species (Ptychadena robeensis, Ptychadena levenorum, Ptychadena erlangeri, and Ptychadena nana) form a monophyletic clade and share the same green/brown polymorphism (Goutte et al., 2021). Using whole-genome resequencing data, we identify and characterize the GCP locus [FOXD3] and show that this genomic region is evolving under long-term balancing selection, resulting in trans-specific polymorphisms."

Inheritance: Goutte et al. (2025) established that "the Green allele being dominant over the brown allele."

Mapping: Goutte et al. (2025) conducted a genome-wide association study (GWAS) to identify the genetic basis of GCP in P. robeensis" using data from 100 animals. The authors "found a primary association peak on chromosome 7, located 52 kb upstream of the gene FoxD3 between two known FoxD3 enhancers, Tarzan and Victor ... . Examination of this genomic region across the population established the full penetrance of the alleles ... ." The authors found that variation at the GCP locus was also associated with coloration in Ptychadena nana, Ptychadena levenorum, and Ptychadena erlangeri.

Molecular basis: Goutte et al. (2025): "the Green haplotype carries a ~10 kb deletion adjacent to the association peak ... ." Expression analysis identified "that FoxD3 expression was elevated in the skin that was or would become green but not in the areas that would remain brown." 

Associated gene: