title: A study of the molecular variants associated with lactase persistence in different Ecuadorian ethnic groups.
abstract: Lactase persistence (LP) is an adaptive trait that certain human populations have acquired in response to lactose consumption in adulthood. The T-13910 variant has been reported as a causal polymorphism in Europeans. The Ecuadorian population has been described as multicultural and multiethnic, comprised of three main ethnic groups (Mestizo, Native Amerindian, and Afro-Ecuadorian). The aim of the study was to identify the molecular basis of LP in these admixed populations for the first time and determine the association between the T-13910 marker and the European ancestry proportion of each ethnic group.
  
  
  
  Genotyping was performed in 741 Ecuadorian individuals by sequencing a 576 bp region around the -13910 position upstream of the LCT gene. The ancestry proportions of Mestizo, Afro-Ecuadorian, and Native Amerindians were calculated using Ancestry Informative Markers and were compared with the diversity panel of the Human Genome Diversity Project.
  
  
  
  LP prevalence calculated from T-13910 allele frequency in Mestizo, Afro-Ecuadorian, and Native Amerindians was 24.4%, 16%, and 12.5%, respectively. The ancestry percentage correlated to the admixture proportion of each ethnic group, and the C/T-13910 genotype frequency was influenced by the European ancestry proportion.
  
  
  
  The presence of the T-13910 polymorphism in the Ecuadorian population suggested that LP was a trait introduced by European migration and inherited by admixture that occurred during the colonization of South America. This variant was not fixed in a population with a history of admixture, and its allele frequency was proportional to the ancestry proportion of each Ecuadorian ethnic group. Am. J. Hum. Biol. 28:774-781, 2016. © 2016Wiley Periodicals, Inc.
authors.affiliation: Instituto de Investigaciones Biomédicas, Facultad de Ciencias de la Salud, Universidad de las Américas, José Queri and de los Granados Av, Quito, Ecuador.
authors.forename: César
authors.initials: C
authors.lastname: Paz-Y-Miño
authors.affiliation: Instituto de Investigaciones Biomédicas, Facultad de Ciencias de la Salud, Universidad de las Américas, José Queri and de los Granados Av, Quito, Ecuador.
authors.forename: Germán
authors.initials: G
authors.lastname: Burgos
authors.affiliation: Instituto de Investigaciones Biomédicas, Facultad de Ciencias de la Salud, Universidad de las Américas, José Queri and de los Granados Av, Quito, Ecuador.
authors.forename: Andrés
authors.initials: A
authors.lastname: López-Cortés
authors.affiliation: Instituto de Investigaciones Biomédicas, Facultad de Ciencias de la Salud, Universidad de las Américas, José Queri and de los Granados Av, Quito, Ecuador.
authors.forename: Camilo
authors.initials: C
authors.lastname: Herrera
authors.affiliation: Laboratorio de Genética Molecular, Cruz Vital - Cruz Roja Ecuatoriana, Papallacta Oe 1-66 and Prensa Av., Quito, Ecuador.
authors.forename: Anibal
authors.initials: A
authors.lastname: Gaviria
authors.affiliation: Instituto de Investigaciones Biomédicas, Facultad de Ciencias de la Salud, Universidad de las Américas, José Queri and de los Granados Av, Quito, Ecuador.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Tejera
authors.affiliation: Instituto de Investigaciones Biomédicas, Facultad de Ciencias de la Salud, Universidad de las Américas, José Queri and de los Granados Av, Quito, Ecuador.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Cabrera-Andrade
mesh_terms: D000328:Adult; D004484:Ecuador; D005260:Female; D014644:Genetic Variation; D006801:Humans; D043322:Lactase / Q000235:genetics* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D044469:Racial Groups / Q000208:ethnology; D055815:Young Adult
chemical_list: D043322:Lactase