A new study in PLoS Biology suggests one of the most common Western European Y halplogroups, R1b1b2, might have originated in Turkey and radiated into Europe with the spread of agriculture during the Neolithic.  This is significant because this haplogroup is the most frequent in Western Europe, and has been posited as a signal from Paleolithic populations who were less impacted by the Neolithic Revolution.

The researchers compared STR variance for this haplotype in several European populations and three Turkish groups, and found a significant correlation (R² = 0.358; p = 0.004) between that variance and the longitude of the population (i.e., how far east the population was located).

Balaresque et al. Figure 1C. Distribution of haplogroup R1b1b STR variance

From the plot, the greatest variance (indicated by the most intense color) within haplogroup R1b1b2 is found in Turkey. They also calculated the time to most recent common ancestor (TMRCA) using STR variance, and found that the oldest lineages, dated between 7,000-7,989 years, are also in Turkey.  The youngest lineage is in Cornwall, dating from 5,460 years ago. The researchers inferred that R1b1b2 originated in Anatolia and spread rapidly into Europe with the spread of agriculture.

Balaresque et al. Figure 1B. Frequency distribution of Haplogroup R1b1b2. More intense color indicate higher frequency.

A couple of things strike me about this study. 1) Haplogroup R1b1b2 reaches it’s highest frequencies in Western Europe, up to 85% of Y-chromosomes in Ireland belong to this haplogroup (Figure 1B). And there are two populations, one in Germany (GE1) and one on the northwest coast of France (FR2), with TMRCA dates in the range of the Turkish dates (7,282 and 7,384 years, respectively). 2) The Turkish data come from Cinnioglu et al. (2004), and consist of samples collected in 90 cities from blood banks, paternity clinics, and university students classified into geographical areas by self-reported “paternal residential heritage” (128).   There is the possibility of introducing error into the sample from this self-reported residence. It’s also possible that the high variance present in the Turkish R1b1b2 lineages reflects more recent immigration.  In addition, TMRCA applies to the molecule, not the populations in which it is found, so while a particular lineage may be 7,000 years old it does not mean that the population has been in that particular location for that length of time. And the authors note, in the supplemental information, “…there is a tendency for TMRCA to be underestimated when single-haplogroup data are considered.”

It’s an interesting hypothesis, though, and I’m curious to see what analyses with additional populations will show.

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Balaresque P, Bowden GR, Adams SM, Leung HY, King TE, Rosser ZH, Goodwin J, Moisan JP, Richard C, Millward A, Demaine AG, Barbujani G, Previderè C, Wilson IJ, Tyler-Smith C, & Jobling MA (2010). A predominantly neolithic origin for European paternal lineages. PLoS biology, 8 (1) PMID: 20087410

Cinnioğlu C, King R, Kivisild T, Kalfoğlu E, Atasoy S, Cavalleri GL, Lillie AS, Roseman CC, Lin AA, Prince K, Oefner PJ, Shen P, Semino O, Cavalli-Sforza LL, & Underhill PA (2004). Excavating Y-chromosome haplotype strata in Anatolia. Human genetics, 114 (2), 127-48 PMID: 14586639