title: Facial asymmetry and genetic ancestry in Latin American admixed populations.
abstract: Fluctuating and directional asymmetry are aspects of morphological variation widely used to infer environmental and genetic factors affecting facial phenotypes. However, the genetic basis and environmental determinants of both asymmetry types is far from being completely known. The analysis of facial asymmetries in admixed individuals can be of help to characterize the impact of a genome's heterozygosity on the developmental basis of both fluctuating and directional asymmetries. Here we characterize the association between genetic ancestry and individual asymmetry on a sample of Latin-American admixed populations. To do so, three-dimensional (3D) facial shape attributes were explored on a sample of 4,104 volunteers aged between 18 and 85 years. Individual ancestry and heterozygosity was estimated using more than 730,000 genome-wide markers. Multivariate techniques applied to geometric morphometric data were used to evaluate the magnitude and significance of directional and fluctuating asymmetry (FA), as well as correlations and multiple regressions aimed to estimate the relationship between facial FA scores and heterozygosity and a set of covariates. Results indicate that directional and FA are both significant, the former being 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 heterozygous individuals exhibit lower levels of asymmetry. Our results highlight the importance of including ancestry-admixture estimators, especially when the analyses are aimed to compare levels of asymmetries on groups differing on socioeconomic levels, as a proxy to estimate developmental noise.
authors.affiliation: Centro Nacional Patagónico, CONICET, Puerto Madryn, Argentina.
authors.forename: Mirsha
authors.initials: M
authors.lastname: Quinto-Sánchez
authors.forename: Kaustubh
authors.initials: K
authors.lastname: Adhikari
authors.forename: Victor
authors.initials: V
authors.lastname: Acuña-Alonzo
authors.forename: Celia
authors.initials: C
authors.lastname: Cintas
authors.forename: Caio Cesar
authors.initials: CC
authors.lastname: Silva de Cerqueira
authors.forename: Virginia
authors.initials: V
authors.lastname: Ramallo
authors.forename: Lucia
authors.initials: L
authors.lastname: Castillo
authors.forename: Arodi
authors.initials: A
authors.lastname: Farrera
authors.forename: Claudia
authors.initials: C
authors.lastname: Jaramillo
authors.forename: Williams
authors.initials: W
authors.lastname: Arias
authors.forename: Macarena
authors.initials: M
authors.lastname: Fuentes
authors.forename: Paola
authors.initials: P
authors.lastname: Everardo
authors.forename: Francisco
authors.initials: F
authors.lastname: de Avila
authors.forename: Jorge
authors.initials: J
authors.lastname: Gomez-Valdés
authors.forename: Tábita
authors.initials: T
authors.lastname: Hünemeier
authors.forename: Shara
authors.initials: S
authors.lastname: Gibbon
authors.forename: Carla
authors.initials: C
authors.lastname: Gallo
authors.forename: Giovanni
authors.initials: G
authors.lastname: Poletti
authors.forename: Javier
authors.initials: J
authors.lastname: Rosique
authors.forename: Maria Cátira
authors.initials: MC
authors.lastname: Bortolini
authors.forename: Samuel
authors.initials: S
authors.lastname: Canizales-Quinteros
authors.forename: Francisco
authors.initials: F
authors.lastname: Rothhammer
authors.forename: Gabriel
authors.initials: G
authors.lastname: Bedoya
authors.forename: Andres
authors.initials: A
authors.lastname: Ruiz-Linares
authors.forename: Rolando
authors.initials: R
authors.lastname: González-José
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D000886:Anthropometry; D005145:Face / Q000033:anatomy & histology / Q000473:pathology; D005146:Facial Asymmetry / Q000235:genetics*; D006630:Hispanic or Latino / Q000235:genetics*; D006801:Humans; D008875:Middle Aged; D025341:Principal Component Analysis; D055815:Young Adult
keywords: Latin America; facial directional asymmetry; facial fluctuating asymmetry; genetic ancestry; geometric morphometrics