Mitochondrial Haplogroup U2d Phylogeny and Distribution

Origin and spread of human mitochondrial DNA haplogroup U7

Human mitochondrial DNA haplogroup U is among the initial maternal founders in Southwest Asia and Europe and one that best indicates matrilineal genetic continuity between late Pleistocene hunter-gatherer groups and present-day populations of Europe. While most haplogroup U subclades are older than 30 thousand years, the comparatively recent coalescence time of the extant variation of haplogroup U7 (~16–19 thousand years ago) suggests that its current distribution is the consequence of more recent dispersal events, despite its wide geographical range across Europe, the Near East and South Asia. Here we report 267 new U7 mitogenomes that – analysed alongside 100 published ones – enable us to discern at least two distinct temporal phases of dispersal, both of which most likely emanated from the Near East. The earlier one began prior to the Holocene (~11.5 thousand years ago) towards South Asia, while the later dispersal took place more recently towards Mediterranean Europe during the Neolithic (~8 thousand years ago). These findings imply that the carriers of haplogroup U7 spread to South Asia and Europe before the suggested Bronze Age expansion of Indo-European languages from the Pontic-Caspian Steppe region.

Mitochondrial DNA genetic diversity and LCT-13910 and deltaF508 CFTR alleles typing in the medieval sample from Poland

We attempted to confirm the resemblance of a local medieval population and to reconstruct their contribution to the formation of the modern Polish population at the DNA level. The HVR I mtDNA sequence and two nuclear alleles, LCT-13910C/T SNP and deltaF508 CFTR, were chosen as markers since the distribution of selected nuclear alleles varies among ethnic groups. A total of 47 specimens were selected from a medieval cemetery in Cedynia (located in the western Polish lowland). Regarding the HVR I profile, the analyzed population differed from the present-day population (P = 0.045, F(st) = 0.0103), in contrast to lactase persistence (LP) based on the LCT-13910T allele, thus indicating the lack of notable frequency changes of this allele during the last millennium (P = 0.141). The sequence of the HVR I mtDNA fragment allowed to identify six major haplogroups including H, U5, T, K, and HV0 within the medieval population of Cedynia which are common in today's central Europe. An analysis of haplogroup frequency and its comparison with modern European populations shows that the studied medieval population is more closely related to Finno-Ugric populations than to the present Polish population. Identification of less common haplogroups, i.e., Z and U2, both atypical of the modern Polish population and of Asian origin, provides evidence for some kind of connections between the studied and foreign populations. Furthermore, a comparison of the available aDNA sequences from medieval Europe suggests that populations differed from one another and a number of data from other locations are required to find out more about the features of the medieval gene pool profile.

Traces of forgotten historical events in mountain communities in Central Italy: A genetic insight

OBJECTIVES

Analysis of human genetic variation in mountain communities can shed light on the peopling of mountainous regions, perhaps revealing whether the remote geographic location spared them from outside invasion and preserved their gene pool from admixture. In this study, we created a model to assess genetic traces of historical events by reconstructing the paternal and maternal genetic history of seven small mountain villages in inland valleys of Central Italy.

METHODS

The communities were selected for their geographic isolation, attested biodemographic stability, and documented history prior to the Roman conquest. We studied the genetic structure by analyzing two hypervariable segments (HVS-I and HVS-II) of the mtDNA D-loop and several informative single nucleotide polymorphisms (SNPs) of the mtDNA coding region in 346 individuals, in addition to 17 short tandem repeats (STRs) and Y-chromosome SNPs in 237 male individuals.

RESULTS

For both uniparental markers, most of the haplogroups originated in Western Europe while some Near Eastern haplogroups were identified at low frequencies. However, there was an evident genetic similarity between the Central Italian samples and Near Eastern populations mainly in the male genetic pool.

CONCLUSIONS

The samples highlight an overall European genetic pattern both for mtDNA and Y chromosome. Notwithstanding this scenario, Y chromosome haplogroup Q, a common paternal lineage in Central/Western Asia but almost Europe-wide absent, was found, suggesting that Central Italy could have hosted a settlement from Anatolia that might be supported by cultural, topographic and genetic evidence.

Human paleogenetics of Europe--the known knowns and the known unknowns

The number of ancient human DNA studies has drastically increased in recent years. This results in a substantial record of mitochondrial sequences available from many prehistoric sites across Western Eurasia, but also growing Y-chromosome and autosomal sequence data. We review the current state of research with specific emphasis on the Holocene population events that likely have shaped the present-day genetic variation in Europe. We reconcile observations from the genetic data with hypotheses about the peopling and settlement history from anthropology and archaeology for various key regions, and also discuss the data in light of evidence from related disciplines, such as modern human genetics, climatology and linguistics.

A western Eurasian male is found in 2000-year-old elite Xiongnu cemetery in Northeast Mongolia

We analyzed mitochondrial DNA (mtDNA), Y-chromosome single nucleotide polymorphisms (Y-SNP), and autosomal short tandem repeats (STR) of three skeletons found in a 2,000-year-old Xiongnu elite cemetery in Duurlig Nars of Northeast Mongolia. This study is one of the first reports of the detailed genetic analysis of ancient human remains using the three types of genetic markers. The DNA analyses revealed that one subject was an ancient male skeleton with maternal U2e1 and paternal R1a1 haplogroups. This is the first genetic evidence that a male of distinctive Indo-European lineages (R1a1) was present in the Xiongnu of Mongolia. This might indicate an Indo-European migration into Northeast Asia 2,000 years ago. Other specimens are a female with mtDNA haplogroup D4 and a male with Y-SNP haplogroup C3 and mtDNA haplogroup D4. Those haplogroups are common in Northeast Asia. There was no close kinship among them. The genetic evidence of U2e1 and R1a1 may help to clarify the migration patterns of Indo-Europeans and ancient East-West contacts of the Xiongnu Empire. Artifacts in the tombs suggested that the Xiongnu had a system of the social stratification. The West Eurasian male might show the racial tolerance of the Xiongnu Empire and some insight into the Xiongnu society.

Mitochondrial DNA variation in an isolated area of Central Italy

BACKGROUND

The genetic variation in Italy is the result of ancient population movement, demographic change, and geography. The increasing possibility of studying the maternal genetic structure of selected Italian population samples at a high level of phylogenetic resolution provides a particularly useful model to assess the presence of genetic traces of the ancient people who lived in Italy in pre-Roman times in present populations

AIM

In this study we reconstructed the genetic maternal history of Jenne and Vallepietra, two mountain communities in the Aniene Valley in the Simbruini Mountains near Rome. Both communities have been spared external invasion due to their geographic location, which very likely preserved the genetic pool of these autochthonous populations.

SUBJECTS AND METHODS

The study population (124 individuals from Jenne and Vallepietra) were investigated for D-loop mtDNA hypervariable segments I (HVS-I) and II (HVS-II) and for informative single nucleotide polymorphisms (SNPs) within the coding region. The detected haplotypes were then compared with those of other Italian, European and Mediterranean populations.

RESULTS

The distribution of mtDNA diversity in Jenne and Vallepietra, although similar to that found in other European populations, shows a basic variability and the typical signs of a certain degree of isolation between them and other populations analysed; in particular, the Vallepietra sample showed an unusually high frequency (71.3%) of mtDNA haplogroups which are typical of Near Eastern and South-Western Asian populations.

CONCLUSION

The high degree of differentiation between the two villages is intriguing, since it suggests a low level of gene flow between them, despite their close geographic proximity and shared linguistic features. The degree of their genetic isolation, also in comparison to other Italian, European and Mediterranean populations, is consistent with isolation among geographically separated populations.

Mitogenomic diversity in Tatars from the Volga-Ural region of Russia

To investigate diversity of mitochondrial gene pool of Tatars inhabiting the territory of the middle Volga River basin, 197 individuals from two populations representing Kazan Tatars and Mishars were subjected for analysis of mitochondrial DNA (mtDNA) control region variation. In addition, 73 mitochondrial genomes of individuals from Mishar population were sequenced completely. It was found that mitochondrial gene pool of the Volga Tatars consists of two parts, but western Eurasian component prevails considerably (84% on average) over eastern Asian one (16%). Eastern Asian mtDNAs detected in Tatars belonged to a heterogeneous set of haplogroups (A, C, D, G, M7, M10, N9a, Y, and Z), although only haplogroups A and D were revealed simultaneously in both populations. Complete mtDNA variation study revealed that the age of western Eurasian haplogroups (such as U4, HV0a, and H) is less than 18,000 years, thus suggesting re-expansion of eastern Europeans soon after the Last Glacial Maximum.