The aim of this work was to describe the phenotypic and genotypic variability related to iris color for the population of Buenos Aires province (Argentina), and to assess the usefulness of current methods of analysis for this country. We studied five Single Nucleotide Polymorphisms (SNPs) included in the IrisPlex kit, in 118 individuals, and we quantified eye color with Digital Iris Analysis Tool. The markers fit Hardy-Weinberg equilibrium for the whole sample, but not for rs12913832 within the group of brown eyes (LR=8.429; p=0.004). We found a remarkable association of HERC2 rs12913832 GG with blue color (p < 0.01) but the other markers did not show any association with iris color. The results for the Buenos Aires population differ from those of other populations of the world for these polymorphisms (p < 0,01). The differences we found might respond to the admixed ethnic composition of Argentina; therefore, methods of analysis used in European populations should be carefully applied when studying the population of Argentina. These findings reaffirm the importance of this investigation in the Argentinian population for people identification based on iris color.

No abstract

Eye color prediction based on an individual's genetic information is of interest in the field of forensic genetics. In recent years, researchers have studied different genes and markers associated with this externally visible characteristic and have developed methods for its prediction. The IrisPlex represents a validated tool for homogeneous populations, though its applicability in populations of mixed ancestry is limited, mainly regarding the prediction of intermediate eye colors. With the aim of validating the applicability of this system in an admixed population from Argentina (n = 302), we analyzed the six single nucleotide variants used in that multiplex for eye color and four additional SNPs, and evaluated its prediction ability. We also performed a genotype-phenotype association analysis. This system proved to be useful when dealing with the extreme ends of the eye color spectrum (blue and brown) but presented difficulties in determining the intermediate phenotypes (green), which were found in a large proportion of our population. We concluded that these genetic tools should be used with caution in admixed populations and that more studies are required in order to improve the prediction of intermediate phenotypes.

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Se ha demostrado que los fenotipos complejos, entre ellos los referidos a ciertas patologías y respuesta a fármacos, están determinados en gran medida por secuencias codificantes del genoma y pueden variar según la ancestría y procedencia geográfica de las poblaciones. En Argentina, la provincia de Chaco presenta una gran diversidad poblacional dada por la coexistencia de comunidades nativas y foráneas, cuya base genética en relación con fenotipos complejos no ha sido estudiada en profundidad. El presente trabajo contribuye al conocimiento de la diversidad de las poblaciones chaqueñas, mostrando diferencias significativas en la variación de los genes OPRM1 y COMT, que modulan la transmisión de la sensación dolorosa y la respuesta a analgésicos. En el futuro, esta diversidad podrá ser tomada en cuenta en decisiones médicas para el tratamiento y prevención del dolor en cada paciente, como es la tendencia de la medicina genómica personalizada.