Assessment of Genetic Ancestry and Population Substructure in Costa Rica by Analysis of Individuals with a Familial History of Mental Disorder

• Published in: Annals of human genetics Vol. 74; no. 6; pp. 516 - 524
• Main Authors: Segura‐Wang, Maia, Raventós, Henriette, Escamilla, Michael, Barrantes, Ramiro
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.11.2010
• Subjects: admixture; Africa; African Continental Ancestry Group - genetics; American Native Continental Ancestry Group - genetics; ancestry; Costa Rica; Ethnic Groups - genetics; European Continental Ancestry Group - genetics; Female; Gene Flow; Gene Frequency; Genetic diversity; Genetic drift; Genetic structure; Genetic Variation; Genetics, Population; Genotype; Humans; Male; Mental disorders; Mental Disorders - genetics; Microsatellite Repeats; Microsatellites; Population genetics; Population levels; Principal Component Analysis; Reproduction; STRs; Africa; Costa Rica
• ISSN: 0003-4800; 1469-1809
• DOI: 10.1111/j.1469-1809.2010.00612.x

Summary The population of Costa Rica has been considered valuable for locating susceptibility genes of complex disorders because of historical events and a gradual admixture process. We present an assessment of 426 unrelated individuals with a familial history of mental disorder and with ancestors born in the Central Valley, genotyped at 730 microsatellites to evaluate genetic diversity, ancestry, and substructure at the general and regional population levels using quantitative methods. Low population substructure was found. Estimated mean ancestry proportions were 54%, 32%, and 13% for European, Amerindian, and African components, respectively, with some regional variation. The FST values obtained confirm the largest genetic similarity to Europeans. Subdivision of the Amerindians into individual populations revealed strong similarity to Chibchan groups. Analysis of the African ancestry showed high similarity to West and Central African populations. Gene ancestries from other African areas were also detected, probably resulting from ancestral admixture within Africa prior to colonial times. Our analyses show, in an ethnohistorical‐genetic context, that gene flow and admixture are important components of Costa Rican population history. The results confirm the need to consider the particular regional genetic structure, the effects of genetic drift and the ancestry when designing and interpreting investigations of genetic traits in this population.