Determination of Phenotype Associated SNPs in the MC1R Gene^*

Abstract

Prediction of physical appearance based on genetic analysis is a very attractive prospect for forensic investigations. Recent studies have proved that there is a significant association between some genetic variants of the melanocortin 1 receptor (MC1R) gene and red hair color. The present study focuses on the potential forensic applicability of variation within this pigment-related gene. Sequencing of the complete MC1R gene was performed on a group of red-haired individuals and controls with different pigmentation. A major role in determination of red hair color is played by two MC1R variants--C451T and C478T. The optimized minisequencing assay for genotyping of the above positions and three other important red hair-related MC1R polymorphisms, C252A, G425A, and G880C was successfully applied to analyze typical forensic specimens. Determination of a homozygous or heterozygous combination can be a good predictor of both red hair color and fair skin of a subject.

Association of Polymorphic Sites in the OCA2 Gene with Eye Colour Using the Tree Scanning Method

“…Moreover, as a very distinguishing human trait, pigmentation is also in the area of interest for forensic science (Jobling & Gill, 2004;Branicki et al 2005). The MC1R gene is the first example of a genetic marker whose prognostic value has already been explored by forensics for red hair colour prediction (Grimes et al 2001;Branicki et al 2007). Another more thoroughly studied pigment gene is OCA2 which is a major gene involved in oculocutaneous albinism in human (Oetting et al 1996).…”

“…Collected samples were subjected to DNA extraction using either the standard organic procedure as described in (Branicki et al 2007) or the silica based method according to the procedure recommended by the manufacturer with minor modifications (A&A Biotechnology, Gdansk, Poland). Briefly, a cotton swab was cut and placed into a 2 ml tube and treated with 700μl of lysis buffer and 20μl of proteinase K (20 mg/mL) for 40 minutes in a waterbath maintained at a temperature of 37…”

Gene–gene interactions contribute to eye colour variation in humans

“…The 24 (SNPs) located in 11 genes, which have been shown to be significantly associated with human pigmentation 10,13,14,16,18,19,[21][22][23][24][25][27][28][29][30][31][32] were genotyped in two multiplex minisequencing assays. The list of the studied polymorphisms is given in Supplementary Table 1.…”

Fisiopatologia do melasma

“…17,30,34,[42][43][44] Outros estudos demonstraram que efélides e lentigos solares são distintos tipos de lesões pigmentadas, pois apresentam diferenças marcantes, nas suas etiologias, porém, variantes gênicas do MC1-R são um fator necessário para o desenvolvimento de efélides, quando desempenham um papel menos importante no caso dos lentigos. 3,30,45,46 Variação relacionada ao gene MC1-R é excepcionalmente alta entre caucasianos e tem um significante impacto no fenótipo pigmentar deste grupo étnico. Cabelos vermelhos (ruivos) têm sido relacionados a alguns alelos, mas recentes estudos indicam que os mesmos genótipos podem expressar diferentes cores de cabelos, dependendo da população estudada.…”

“…Cabelos vermelhos (ruivos) têm sido relacionados a alguns alelos, mas recentes estudos indicam que os mesmos genótipos podem expressar diferentes cores de cabelos, dependendo da população estudada. 3,44 MC1-R está expresso, abundantemente, em células de melanoma humano e de ratos e em níveis significativamente mais baixos em melanócitos de ratos. Mais recentemente, foi demonstrado em glân-dulas normais da pele humana e folículos capilares, bem como em malformações e neoplasmas da pele.…”