title: mtDNA and the origin of Caucasians: identification of ancient Caucasian-specific haplogroups, one of which is prone to a recurrent somatic duplication in the D-loop region.
abstract: mtDNA sequence variation was examined in 175 Caucasians from the United States and Canada by PCR amplification and high-resolution restriction-endonuclease analysis. The majority of the Caucasian mtDNAs were subsumed within four mtDNA lineages (haplogroups) defined by mutations that are rarely seen in Africans and Mongoloids. The sequence divergence of these haplogroups indicates that they arose early in Caucasian radiation and gave raise to modern European mtDNAs. Although ancient, none of these haplogroups is old enough to be compatible with a Neanderthal origin, suggesting that Homo sapiens sapiens displaced H. s. neanderthaliensis, rather than mixed with it. The mtDNAs of one of these haplogroups have a unique homoplasmic insertion between nucleotide pair (np) 573 and np 574, within the D-loop control region. This insertion makes these mtDNAs prone to a somatic mutation that duplicates a 270-bp portion of the D-loop region between np 309 and np 572. This finding suggests that certain nonpathogenic mtDNA mutations could predispose individuals to mtDNA rearrangements.
authors.affiliation: Department of Genetics and Molecular Medicine, Emory University School of Medicine, Atlanta, GA 30322.
authors.forename: A
authors.initials: A
authors.lastname: Torroni
authors.forename: M T
authors.initials: MT
authors.lastname: Lott
authors.forename: M F
authors.initials: MF
authors.lastname: Cabell
authors.forename: Y S
authors.initials: YS
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Lavergne
authors.forename: D C
authors.initials: DC
authors.lastname: Wallace
mesh_terms: D000818:Animals; D001106:Archaeology; D044466:Asian People / Q000235:genetics; D001483:Base Sequence; D005075:Biological Evolution; D044383:Black People / Q000235:genetics; D002170:Canada; D002869:Chromosome Aberrations; D017931:DNA Primers; D004272:DNA, Mitochondrial / Q000032:analysis / Q000235:genetics*; D014644:Genetic Variation; D006239:Haplotypes / Q000235:genetics; D015186:Hominidae / Q000235:genetics*; D006801:Humans; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods*; D015183:Restriction Mapping; D013995:Time; D014481:United States; D044465:White People / Q000235:genetics*; D001741:Black or African American
chemical_list: D017931:DNA Primers; D004272:DNA, Mitochondrial