Mitochondrial Genome Diversity of Native Americans Supports a Single Early Entry of Founder Populations into America

There is general agreement that the Native American founder populations migrated from Asia into America through Beringia sometime during the Pleistocene, but the hypotheses concerning the ages and the number of these migrations and the size of the ancestral populations are surrounded by controversy. DNA sequence variations of several regions of the genome of Native Americans, especially in the mitochondrial DNA (mtDNA) control region, have been studied as a tool to help answer these questions. However, the small number of nucleotides studied and the nonclocklike rate of mtDNA control-region evolution impose several limitations to these results. Here we provide the sequence analysis of a continuous region of 8.8 kb of the mtDNA outside the D-loop for 40 individuals, 30 of whom are Native Americans whose mtDNA belongs to the four founder haplogroups. Haplogroups A, B, and C form monophyletic clades, but the five haplogroup D sequences have unstable positions and usually do not group together. The high degree of similarity in the nucleotide diversity and time of differentiation (i.e., ∼21,000 years before present) of these four haplogroups support a common origin for these sequences and suggest that the populations who harbor them may also have a common history. Additional evidence supports the idea that this age of differentiation coincides with the process of colonization of the New World and supports the hypothesis of a single and early entry of the ancestral Asian population into the Americas

A importância de ser Uros: movimentos indígenas, políticas de identidade e pesquisa genética nos Andes Peruanos

O objetivo deste artigo é explorar as inter-relações entre a pesquisa genética, as lutas políticas de movimentos indígenas e os processos de formação de identidade étnica. Em particular, visa analisar as condições sociais que levaram à colaboração entre os uros, um grupo indígena que habita as ilhas flutuantes do lago Titicaca (Peru), e pesquisadores do projeto Genográfico. Os uros, cujas reivindicações de uma identidade étnica diferenciada eram altamente contestadas no âmbito local, se associaram aos geneticistas com o objetivo de obter um apoio científico para a afirmação dessa identidade e como parte das suas estratégias políticas e demandas territoriais. Assim, esse caso contribui ao maior entendimento da incorporação da pesquisa genética dentro de políticas conceituais travadas em torno das identidades étnicas, bem como da articulação do conhecimento genético com registros preexistentes para definir tais identidadesThe objective of this paper is to explore the interrelations between genetic research with human populations, the political strategies of indigenous movements and processes of identity formation. In particular, it will analyse the social conditions that have resulted in the collaboration between the Uros, an indigenous group living on the floating islands of Lake Titicaca (Peru), and researchers of the Genographic project. The Uros, whose claims to a differentiated ethnic identity were highly contested within the local context, engaged with geneticists with the aim to obtain scientific support for this identity. This was part of their political strategies for their territorial rights. As such, this case offers new insights into the incorporation of genetic research within the conceptual politics waged around ethnic identities, as well as the articulation of genetic knowledge with pre-existing registers to define such identitie