Genetic admixture estimates by Alu elements in Afro-Colombian and Mestizo populations from Antioquia, Colombia

Abstract

Aim: This work was intended to gain insights into the admixture processes occurring in Latin American populations by examining the genetic profiles of two ethnic groups from Antioquia (Colombia).

Subjects and methods: To analyse the genetic variability, eight Alu insertions were typed in 64 Afro-Colombians and a reference group of 34 Hispanics (Mestizos). Admixture proportions were estimated using the Weighted Least Squares and the Gene Identity methods. The usefulness of the Alu elements as Ancestry Informative Markers (AIMs) was evaluated through differences in weighted allelic frequencies (δ values) and by hierarchical analysis of the molecular variance (AMOVA).

Results: The Afro-Colombian gene pool was largely determined by the African component (88.5–88.8%), but the most prominent feature was the null contribution of European genes. Mestizos were characterized by a major European component (60.0–63.8%) and a comparatively low proportion of Amerindian (19.2–20.7%) and African (17.0–19.3%) genes. Five of the Alu loci examined (ACE, APO, FXIIIB, PV92 and TPA25) showed an adequate resolving power to differentiate between continental groups, as indicated by δ values and AMOVA results.

Conclusions: The peculiarity of the Afro-Colombian gene pool seems to be associated with intense genetic drift episodes that occurred in isolated communities founded by small groups of runaway slaves. ACE, APO, FXIIIB, PV92 and TPA25 could be efficiently utilized in studies dealing with demographic history and biogeographical ancestry in human populations.

Keywords::

• Genetic admixture
• Alu insertions
• Ancestry Informative Markers
• Colombia
• Afro-Colombian

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.