title: Genetic signature of natural selection in first Americans.
abstract: When humans moved from Asia toward the Americas over 18,000 y ago and eventually peopled the New World they encountered a new environment with extreme climate conditions and distinct dietary resources. These environmental and dietary pressures may have led to instances of genetic adaptation with the potential to influence the phenotypic variation in extant Native American populations. An example of such an event is the evolution of the fatty acid desaturases (FADS) genes, which have been claimed to harbor signals of positive selection in Inuit populations due to adaptation to the cold Greenland Arctic climate and to a protein-rich diet. Because there was evidence of intercontinental variation in this genetic region, with indications of positive selection for its variants, we decided to compare the Inuit findings with other Native American data. Here, we use several lines of evidence to show that the signal of FADS-positive selection is not restricted to the Arctic but instead is broadly observed throughout the Americas. The shared signature of selection among populations living in such a diverse range of environments is likely due to a single and strong instance of local adaptation that took place in the common ancestral population before their entrance into the New World. These first Americans peopled the whole continent and spread this adaptive variant across a diverse set of environments.
authors.affiliation: Department of Biological Sciences, Columbia University, New York, NY 10027.
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Amorim
authors.affiliation: Departmento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, 03178-200 São Paulo, Brazil.
authors.forename: Kelly
authors.initials: K
authors.lastname: Nunes
authors.affiliation: Departmento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, 03178-200 São Paulo, Brazil.
authors.forename: Diogo
authors.initials: D
authors.lastname: Meyer
authors.affiliation: Institut de Biologia Evolutiva, Departament de Ciències Experimentals i de la Salut, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Comas
authors.affiliation: Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brazil.
authors.forename: Maria Cátira
authors.initials: MC
authors.lastname: Bortolini
authors.affiliation: Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, 91501-970 Porto Alegre, Brazil francisco.salzano@ufrgs.br hunemeier@usp.br.
authors.forename: Francisco Mauro
authors.initials: FM
authors.lastname: Salzano
authors.affiliation: Departmento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, 03178-200 São Paulo, Brazil; francisco.salzano@ufrgs.br hunemeier@usp.br.
authors.forename: Tábita
authors.initials: T
authors.lastname: Hünemeier
mesh_terms: D044466:Asian People / Q000235:genetics / Q000266:history; D044383:Black People / Q000235:genetics / Q000266:history; D002874:Chromosome Mapping; D002877:Chromosomes, Human; D044943:Fatty Acid Desaturases / Q000235:genetics*; D005828:Genetics, Population; D049690:History, Ancient; D063426:Human Migration / Q000266:history*; D006801:Humans; D007197:Indians, Central American / Q000235:genetics* / Q000266:history; D007198:Indians, North American / Q000235:genetics* / Q000266:history; D007199:Indians, South American / Q000235:genetics* / Q000266:history; D004930:Inuit / Q000235:genetics* / Q000266:history; D020641:Polymorphism, Single Nucleotide; D012641:Selection, Genetic; D044465:White People / Q000235:genetics / Q000266:history
chemical_list: D044943:Fatty Acid Desaturases
keywords: first Americans; genetics; natural selection; peopling of America