Two pennyworth on Slavic kinship and origins

Dec 2014
The Slavs are an Indo-European ethno-linguistic group living in Central Europe, Eastern Europe, Southeast Europe, North Asia and Central Asia, who speak the Indo-European Slavic languages, and share, to varying degrees, certain cultural traits and historical backgrounds. From the early 6th century they spread to inhabit most of Central and Eastern Europe and Southeast Europe. Slavic groups also ventured as far as Scandinavia, constituting elements amongst the Vikings; while at the other geographic extreme, Slavic mercenaries fighting for the Byzantines and Arabs settled Asia Minor and even as far as Syria. Later, East Slavs (specifically, Russians and Ukrainians) colonized Siberia and Central Asia. Every Slavic ethnicity has emigrated to other parts of the world. Over half of Europe's territory is inhabited by Slavic-speaking communities.

New article (from November 2014) about Serbs (who speak practically the same language as Croats and it is possible that they came together to the Balkans) published in the American Journal of Physical Anthropology:

Mitochondrial DNA perspective of Serbian genetic diversity | ReadCube Articles


Although south-Slavic populations have been studied to date from various aspects, the population of Serbia, occupying the central part of the Balkan Peninsula, is still genetically understudied at least at the level of mitochondrial DNA (mtDNA) variation. We analyzed polymorphisms of the first and the second mtDNA hypervariable segments (HVS-I and HVS-II) and informative coding-region markers in 139 Serbians to shed more light on their mtDNA variability, and used available data on other Slavic and neighboring non-Slavic populations to assess their interrelations in a broader European context. The contemporary Serbian mtDNA profile is consistent with the general European maternal landscape having a substantial proportion of shared haplotypes with eastern, central, and southern European populations. Serbian population was characterized as an important link between easternmost and westernmost south-Slavic populations due to the observed lack of genetic differentiation with all other south-Slavic populations and its geographical positioning within the Balkan Peninsula. An increased heterogeneity of south Slavs, most likely mirroring turbulent demographic events within the Balkan Peninsula over time (i.e., frequent admixture and differential introgression of various gene pools), and a marked geographical stratification of Slavs to south-, east-, and west-Slavic groups, were also found. A phylogeographic analyses of 20 completely sequenced Serbian mitochondrial genomes revealed not only the presence of mtDNA lineages predominantly found within the Slavic gene pool (U4a2a*, U4a2a1, U4a2c, U4a2g, HV10), supporting a common Slavic origin, but also lineages that may have originated within the southern Europe (H5*, H5e1, H5a1v) and the Balkan Peninsula in particular (H6a2b and L2a1k). Am J Phys Anthropol, 2014. © 2014 Wiley Periodicals, Inc.

The Slavs are currently the prevalent ethnic group in Europe inhabiting a rather large part of the continent, i.e., central, eastern and southeastern Europe. The questions regarding their ethnic history, however, are still open since historical, archaeological, ethnographic, and linguistic data accumulated to date support their common origin but do not provide unambiguous evidence regarding the time of their formation and their homeland (see Mielnik-Sikorska et al. 2013 for references). Nonetheless, new insights into the history of Slavs may be gained by analyzing variability at the molecular level present in their contemporary populations (e.g., Pericic et al., 2005; Malyarchuk et al., 2008a; Kushniarevich et al., 2013; Mielnik-Sikorska et al., 2013). This is possible because genetic profiles of extant populations harbor genetic footprints of past events, and that cognition strongly marked not only studies of Slavic but of all human populations. Uniparentally inherited genetic systems, such as mitochondrial (mtDNA) genome and non-recombining portion of the Y chromosome (NRY), turned out to be particularly suitable for such inferences especially when employed for a phylogeographic approach implemented initially by Avise (2000). The power of molecular data in providing answers on history of human populations may further be increased by analyzing ancient DNAs along with those of contemporary individuals (reviewed in Pala et al., 2014). Molecular data contributed toward understanding that upon the initial colonization of Europe by anatomically modern humans, postglacial expansions from glacial refugia along with frequent admixture and introgression of gene pools of various populations as well as Mesolithic to Neolithic transition have had a major impact on assembling the contemporary genetic landscape of Europe (reviewed in Pinhasi et al., 2012). Furthermore, along with archaeological data, they provided support for delineation of southeastern Europe as a region which played an important role in all these events that represent milestones of the historical development of contemporary European gene pool (...)

And now let's check the origin of this U4 mtDNA:

mtDNA lineages predominantly found within the Slavic gene pool (U4a2a*, U4a2a1, U4a2c, U4a2g, HV10), supporting a common Slavic origin
Here is an excerpt about the origins of U4 mtDNA haplogroup, in the context of Ancient archaeological cultures:

Haplogroup U4 (mtDNA) - Eupedia

This article was last updated in March 2014:

During the Neolithic period U4 stands out by its absence from the hundreds of [European] samples tested to date, except for one Late Neolithic/Chalcolithic sample (c. 3250 BCE) from Catalonia and one from Portugal (3000 BCE). Along with Cantabria, Catalonia and Portugal also happen to be the regions of Iberia where U4 is the most common today. As there appears to be a continuity in these regions since the Mesolithic, it is possible that Iberian U4, or West European U4 in general, was brought by nomadic tribes of hunter-gatherers belonging to old, pre-Indo-European subclades of R1a, such as SRY1532.2 or M17. Originally from eastern Europe, these R1a/U4 people would have crossed all Europe and survived in isolated pockets of western Europe from the Neolithic onwards.

Haplogroup U4 make a strong come back during the Bronze Age, where it is found at high frequency among remains from the Proto-Indo-European Corded Ware culture and Catacomb culture (a staggering 25% of the 28 samples, see Wilde et al. 2014), both associated with the diffusion of R1a to Central Europe and Scandinavia, and in the Unetice culture, thought to be the first predominantly R1b culture around what is now Germany. The subclades identified for the Corded Ware and Unetice cultures were respectively U4a1 [Corded Ware] and U4c1 [Unetice]. Both of these subclades are also found in Central Asia today, confirming the Indo-European connection.

U4 was also found in the Yamna culture, the presumed homeland of Proto-Indo-European speakers in the Pontic Steppe. The Volga-Ural region played a major role in Bronze Age PIE cultures, and remained fairly isolated from the subsequent population movements within Europe. The same is true for the central Caucasus region, such as Georgia and southern Daghestan, which received relatively little influx of foreign genes after the Bronze Age. The fact that U4 is many times more prevalent in these regions today also suggest a higher frequency among Bronze Age PIE speakers. During the Yamna and Maykop periods (3700-2500 BCE), R1a and R1b people would have intermingled in Pontic-Caspian Steppes and North Caucasus, explaining why U4 is also found among R1b populations, although at a lower frequency than among R1a populations. In modern France and northern Italy, the percentage of U4 looks directly proportional to the frequency of combined haplogroups R1a and R1b.

Interesting, Fernández et al. (2005) also found two U4 individuals (including one U4a2b) in Sumerian city of Mari in Syria dating from the Early Dynastic Period (2900-2700 BCE), just after the Uruk collapse, which could have been caused by early Indo-European incursions into the Near East.

U4 maternal lineages were found in Bronze Age cultures associated with the Indo-European migrations in Central Asia and Siberia, such as the Andronovo and Karasuk cultures (Keyser 2009), but also in in the Tarim basin in north-west China during the Early Iron Age (Zhang 2010).
All Slavic people appear to share three subclades of R1a - M458, M558 and Z282:

But Z282 seems to be perhaps Balto-Slavic rather than exclusively Slavic in origin:

Large version in the link: R1a in Slavic populations