Categories: Pigmentation phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 605123 (gene)

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal incomplete dominant

Disease-related: yes

Key variant known: no

Cross-species summary: Iridophoromas are tumours of pigment-producing cells

Species-specific name: 'Lemon Frost'

Species-specific symbol: lf

Species-specific description: Guo et al. (2021): "Lemon Frost geckos have increased white body coloration with brightened yellow and orange areas. This morph also displays a high incidence of iridophoroma, a tumor of white-colored cells. We obtained phenotype information and DNA samples from geckos in a large breeding colony and used genome sequencing and genetic linkage analysis to localize the Lemon Frost mutation to a single locus."

Inheritance: Guo et al. (2021): "A male leopard gecko carrying the lemon frost (lf) allele, Mr. Frosty ..., was crossed to 12 female leopard geckos of different genetic backgrounds. The F1 progeny, which were heterozygous for the lf allele, were backcrossed to the same maternal lines or intercrossed to establish a colony of more than 900 animals. ... The lf allele is semidominant, as homozygous mutants have more pronounced phenotypes than do heterozygotes."

Mapping: Guo et al. (2021) "used restriction site-associated DNA sequencing (RAD-Seq) to genotype 188 animals from the breeding pedigree ... . To narrow down the location of the causal gene within this genomic region, we used whole genome sequencing and homozygosity mapping. ... results indicate that scaffold 996 contains the Lemon Frost mutation. ... The genomic interval spanning positions 570kb-640kb on scaffold 996 contains a single gene, SPINT1."

Molecular basis: Guo et al. (2021): "The Lemon Frost SPINT1 allele differs from the reference genome assembly at two positions in the exons, as well as at 147 positions in the introns and the 3’UTR .... Both differences in the coding sequence of SPINT1 are synonymous. Notable differences in non-coding regions include 7 large insertion/deletions (indels) in the introns and a 13-nucleotide insertion in the 3’UTR (CAAGTGTATGTAT)."

Associated gene: