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Combined use of biallelic and microsatellite Y-chromosome polymorphisms in finding affinities among African populations is discussed. Seven biallelic polymorphic sites were studied to define Y-chromosome haplotypes. Data was combined with those from four dinucleotide-repeat polymorphisms. The object was to establish Y-chromosome compound superhaplotypes. Geographic closeness seems better as a predictor of genetic affinity than language and genetic similarities.

An analysis based on two systems for describing the human mitochondrial genome (mtDNA) has been carried out using 95 samples from the Near East and northwest Caucasus. One procedure is assaying restriction fragment length polymorphisms (RFLPs) all through the genome and the other is sequencing of parts of the control region (CR). The concordance of the two systems has been demonstrated. Variation in mtDNA is used to infer histories of peoples. The most refined phylogeny so far found for west Eurasian mtDNA has been presented and a nomenclature described and applied for mtDNA clusters. Hypervariable nucleotides have been identified. Relative mutation rates of the two systems have been evaluated with ambiguities identified. Berber speakers were sampled and a identification of signature mutations for each cluster led to a hierarchical scheme for finding cluster composition. The main indigenous North African cluster is a sister group to the most ancient cluster of European mRNAs. It diverged about 50,000 years ago.

A possible ancient link between Europe/Western Asia and North America in mtDNA haplogroup X is discussed with information on investigation of the origins, continental relationships and diversity of the haplogroup. Investigation was carried out with mtDNA high-resolution RFLP and complete control region sequence analysis of 14 putative European haplogroup X and 22 putative Native American haplogroup X mtDNAs and identified a consensus haplogroup X motif characterizing Native American and European samples, so some Native American founders may have had Caucasian ancestry.

Common descent followed by molecular radiation accounts for most of the phenetic relationships among haplotypes in four Y-linked dinucleotide microsatellites among 908 men from Europe, northern Africa, and western Asia. Six large networks and two small ones emerged. The complete diversity within a sample can be partitioned using this technique. A low level of homoplasy is found among dinucleotide microsatellite haplotypes. Populations are highly structured in terms of Y-chromosomal network frequencies.

To shed light on the structure of the basal backbone of the human Y chromosome phylogeny, we sequenced about 200 kb of the male-specific region of the human Y chromosome (MSY) from each of seven Y chromosomes belonging to clades A1, A2, A3, and BT. We detected 146 biallelic variant sites through this analysis. We used these variants to construct a patrilineal tree, without taking into account any previously reported information regarding the phylogenetic relationships among the seven Y chromosomes here analyzed. There are several key changes at the basal nodes as compared with the most recent reference Y chromosome tree. A different position of the root was determined, with important implications for the origin of human Y chromosome diversity. An estimate of 142 KY was obtained for the coalescence time of the revised MSY tree, which is earlier than that obtained in previous studies and easier to reconcile with plausible scenarios of modern human origin. The number of deep branchings leading to African-specific clades has doubled, further strengthening the MSY-based evidence for a modern human origin in the African continent. An analysis of 2204 African DNA samples showed that the deepest clades of the revised MSY phylogeny are currently found in central and northwest Africa, opening new perspectives on early human presence in the continent. [Copyright &y& Elsevier]

Mitochondrial HVS-I sequences from 10,365 subjects belonging to 56 populations/geographical regions of western Eurasia and northern Africa were first surveyed for the presence of the T C transition at nucleotide position 16298, a mutation which has previously been shown to characterize haplogroup V mtDNAs. All mtDNAs with this mutation were then screened for a number of diagnostic RFLP sites, revealing two major subsets of mtDNAs. One is haplogroup V proper, and the other has been termed "preV." since it predates V phylogenetically. The rather uncommon pre*V tends to be scattered throughout Europe (and northwestern Africa), whereas V attains two peaks of frequency: one situated in southwestern Europe and one in the Saami of northern Scandinavia. Geographical distributions and ages support the scenario that pre*V originated in Europe before the Last Glacial Maximum (LGM), whereas the more recently derived haplogroup V arose in a southwestern European refugium soon after the LGM. The arrival of V in eastern/central Europe, however, occurred much later, possibly with (post-)Neolithic contacts. The distribution of haplogroup V mtDNAs in modern European populations would thus, at least in part, reflect the pattern of postglacial human recolonization from that refugium, affecting even the Saami. Overall, the present study shows that the dissection of mtDNA variation into small and well-defined evolutionary units is an essential step in the identification of spatial frequency patterns. Mass screening of a few markers identified using complete mtDNA sequences promises to be an efficient strategy for inferring features of human prehistory. [ABSTRACT FROM AUTHOR]