High levels of Paleolithic Y-chromosome lineages characterize Serbia

Whether present-day European genetic variation and its distribution patterns can be attributed primarily to the initial peopling of Europe by anatomically modern humans during the Paleolithic, or to latter Near Eastern Neolithic input is still the subject of debate. Southeastern Europe has been a crossroads for several cultures since Paleolithic times and the Balkans, specifically, would have been part of the route used by Neolithic farmers to enter Europe. Given its geographic location in the heart of the Balkan Peninsula at the intersection of Central and Southeastern Europe, Serbia represents a key geographical location that may provide insight to elucidate the interactions between indigenous Paleolithic people and agricultural colonists from the Fertile Crescent. In this study, we examine, for the first time, the Y-chromosome constitution of the general Serbian population. A total of 103 individuals were sampled and their DNA analyzed for 104 Y-chromosome bi-allelic markers and 17 associated STR loci. Our results indicate that approximately 58% of Serbian Y-chromosomes (I1-M253, I2a-P37.2 and R1a1a-M198) belong to lineages believed to be pre-Neolithic. On the other hand, the signature of putative Near Eastern Neolithic lineages, including E1b1b1a1-M78, G2a-P15, J1-M267, J2-M172 and R1b1a2-M269 accounts for 39% of the Y-chromosome. Haplogroup frequency distributions in Western and Eastern Europe reveal a spotted landscape of paleolithic Y chromosomes, undermining continental-wide generalizations. Furthermore, an examination of the distribution of Y-chromosome filiations in Europe indicates extreme levels of Paleolithic lineages in a region encompassing Serbia, Bosnia-Herzegovina and Croatia, possibly the result of Neolithic migrations encroaching on Paleolithic populations against the Adriatic Sea.     

Helix VIII of NhaA Na(+)/H(+) antiporter participates in the periplasmic cation passage and pH regulation of the antiporter

The crystal structure of Escherichia coli NhaA determined at pH 4 has provided insights into the mechanism of activity of a pH-regulated Na⁺/H⁺ antiporter. However, because NhaA is active at physiological pH (pH 6.5-8.5), many questions related to the active state of NhaA have remained unanswered. Our Cys scanning of the highly conserved transmembrane VIII at physiological pH reveals that (1) the Cys replacement G230C significantly increases the apparent K_m of the antiporter to both Na⁺ (10-fold) and Li⁺ (6-fold). (2) Variants G223C and G230C cause a drastic alkaline shift of the pH profile of NhaA by 1 pH unit. (3) Residues Gly223-Ala226 line a periplasmic funnel at physiological pH as they do at pH 4. Both were modified by membrane-impermeant negatively charged 2-sulfonatoethyl methanethiosulfonate and positively charged 2-(trimethyl ammonium)-ethylmethanethiosulfonate sulfhydryl reagents that could reach Cys replacements from the periplasm via water-filled funnels only, whereas other Cys replacements on helix VIII were not accessible/reactive to the reagents. (4) Remarkably, the modification of variant V224C by 2-sulfonatoethyl methanethiosulfonate or 2-(trimethyl ammonium)-ethylmethanethiosulfonate totally inhibited antiporter activity, while N-ethyl maleimide modification had a very small effect on NhaA activity. Hence, the size—rather than the chemical modification or the charge—of the larger reagents interferes with the passage of ions through the periplasmic funnel. Taken together, our results at physiological pH reveal that amino acid residues in transmembrane VIII contribute to the cation passage of NhaA and its pH regulation.     

New dendroarchaeological evidence of water well constructions reveals advanced Early Neolithic craftsman skills

The first European settlements accompanied by crop and livestock farming occurred approximately 7500 years ago. In this agrarian society, wood was one of the most important raw materials, most notably for construction, but only a little is known about wood use and woodworking technology. Hence, archaeological wooden finds are of particular importance. Dendroarchaeological studies combine the analysis of external and internal characteristics of archaeological wood: traces of tools on the wooden surfaces and the shape of timbers provide information about woodworking techniques, the tree rings allow dendrochronological dating and provide a paleoecological archive. In 2015 and 2016, two water wells with wooden linings from the Early Neolithic Period were discovered in the Czech Republic close to the towns of Velim (Bohemia) and Uničov (Moravia). The timbers were excellently preserved under waterlogged conditions. Here, we present a dendroarchaeological study including tree-ring and woodworking analyses. Furthermore, we consider former forest species composition. Overall, 15 lumbers from both wells were successfully dated by dendrochronology. The oaks used for the wells from Velim and Uničov were felled in 5196/5195 BCE and 5093–5085 BCE, respectively. Additionally, the taxa of 1859 wooden fragments, such as charcoals, branches and chips, were wood anatomically identified. The well lining from Velim with a hollowed tree trunk is already known from other Central European locations. In contrast, the construction from Uničov is unique for this period. Until now, the advanced construction design formed by four corner posts with longitudinal grooves and inserted horizontal planks was only known several thousands years later. The Early Neolithic wells from Uničov and Velim are the oldest archaeological discoveries of wooden artefacts in the Czech Republic that have been dendrochronologically dated. The tree-ring width series extend the Czech oak tree-ring width chronology more than 300 years into the past.