Mitochondrial genome variation and the origin of modern humans

Abstract

The analysis of mitochondrial DNA (mtDNA) has been a potent tool in our understanding of human evolution, owing to characteristics such as high copy number, apparent lack of recombination, high substitution rate and maternal mode of inheritance. However, almost all studies of human evolution based on mtDNA sequencing have been confined to the control region, which constitutes less than 7% of the mitochondrial genome. These studies are complicated by the extreme variation in substitution rate between sites, and the consequence of parallel mutations causing difficulties in the estimation of genetic distance and making phylogenetic inferences questionable. Most comprehensive studies of the human mitochondrial molecule have been carried out through restriction-fragment length polymorphism analysis, providing data that are ill suited to estimations of mutation rate and therefore the timing of evolutionary events. Here, to improve the information obtained from the mitochondrial molecule for studies of human evolution, we describe the global mtDNA diversity in humans based on analyses of the complete mtDNA sequence of 53 humans of diverse origins. Our mtDNA data, in comparison with those of a parallel study of the Xq13.3 region in the same individuals, provide a concurrent view on human evolution with respect to the age of modern humans.

Genetic variation, classification and 'race'

“…This allows us to 'root' the tree and shows that the root falls closest to African populations. All of these findings, which are in accord with many other studies based on different types of genetic variation assessed in different samples of humans [25][26][27][28] , support an evolutionary scenario in which anatomically modern humans evolved first in Africa, accumulating genetic diversity. A small subset of the African population then left the continent, probably experienced a population bottleneck and founded anatomically modern human populations in the rest of the world 29 .…”

Bridging two scholarly islands enriches both: COI DNA barcodes for species identification versus human mitochondrial variation for the study of migrations and pathologies

“…(2002)560435 European, 56 African, 52 Native American, 17 AsianIngman et al. (2000)53African, European, Asian, New WorldTotal9413Permissions: John Wiley & Sons, Ltd…”

A large-scale screening of the normalized mammalian mitochondrial gene expression profiles

“…Complete mammalian mitochondrial genomes generally established as the ' reference ' sequences were downloaded from the GenBank database (NCBI; http ://w ww.ncbi.nlm.nih.gov/entrez/) as the following : Homo sapiens, accession number X93334 (a Caucasian from southern Sweden (Lund, Ska˚ne) ; Arnason et al, 1996 ;Nilsson et al, 2003) and NC_001807 (an African (Yoruba ethnic group) ; Ingman et al, 2000) ; Mus musculus, AB042432 (Mizutani et al, 2001) and J01420 (Bibb et al, 1981) ; Rattus norvegicus, AY172581 (Rat Genome Sequencing Project Consortium, 2004) and NC_001665 (Gadaleta et al, 1989) ; Bos taurus, AY526085 ; and Sus scrofa, NC_000845 (Lin et al, 1999). Single nucleotide polymorphisms (SNPs) or genetic variations in mitochondrial sequences were addressed using the BLAST2 alignment tool (NCBI; http://www.ncbi.nlm.nih.gov/blast/bl2seq/bl2.html ; Tatusova & Madden, 1999).…”