Facial asymmetry and genetic ancestry in Latin American admixed populations

MIRSHA QUINTO SÁNCHEZ; KAUSTUBH ADHIKARI; ACUÑA-ALONZO, V; CELIA CINTAS; CAIO C. SILVA DE CERQUEIRA; VIRGÍNIA RAMALLO; CASTILLO, LUCIA; FARRERA, ARODI; CLAUDIA JARAMILLO; WILLIAM ARIAS; MACARENA FUENTES; PAOLA EVERARDO; FRANCISCO DE AVILA; GOMEZ-VALDES, JORGE; TÁBITA HUNEMEIER; SAHRA GIBBON; CARLA GALLO; GIOVANNI POLETTI; JAVIER ROSIQUE; MARÍA CÁTIRA BORTOLINI; SAMUEL CANIZALES-QUINTEROS; FRANCISCO ROTHHAMMER; GABRIEL BEDOYA; ANDRÉS RUIZ-LINARES; GONZÁLEZ JOSÉ, ROLANDO

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Lugar: New York; Año: 2015 vol. 157 p. 58 - 70

0002-9483

Fluctuating and directional asymmetry are aspects of morphological variation widely used to infer environmental and genetic stress effects in facial phenotypes. However, the genetic basis of both asymmetry types is far from being completely known. The exploration of facial asymmetric morphospace of admixed individuals is of help to characterize the impact of a genome?s heterozygote architecture on the developmental basis of both fluctuating and directional asymmetries. Here we characterize the association among genetic ancestry and asymmetry on a sample of Latin-American Mestizo populations. To do so, three-dimensional facial shape attributes were explored on a sample of 2778 volunteers aged between 18 and 60 years. Individual ancestry was estimated by genotyping thirty genetic Ancestry Individual Markers specifically selected to estimate African, European, and Native American ancestry. Multivariate techniques applied to geometric morphometric data were implemented to evaluate the magnitude and significance of directional and fluctuating asymmetry, and to compute the multivariate regression of asymmetry on the amount of European, Amerindian, and African ancestry. Results indicate that directional and fluctuating asymmetry are both significant effects, being the former the strongest expression of asymmetry in this sample. In addition, our analyses suggest that there are some specific patterns of facial asymmetries characterizing the different ancestry groups. Finally, we find that more admixed individuals exhibit lower levels of asymmetry. Our results highlight the importance of correcting for ancestry-admixture, especially when the analyses are aimed to compare levels of asymmetries on groups differing on socioeconomic levels, as a proxy to estimate developmental noise.