Fig. 1.

Probabilities of obtaining F_ST equal to or greater than that observed (0.00551) between 60 Eneolithic (ca. 6,500–5,000 y ago) and Bronze Age (ca. 5,000–4,000 y ago) samples from the Pontic–Caspian steppe, and a combined sample of 246 homologous modern sequences from the same geographic region, across a range of assumed ancestral population size combinations. Two phases of exponential growth were modeled, the first after the initial colonization of Europe 45,000 y ago, of assumed effective female population size N_UP (y axis), and ending when farming began in the region considered 7,000 y ago, when the assumed effective female population size was N_N (x axis), and the second leading up to the present, when the assumed effective female population size is 5,444,812. The initial colonizers of Europe were sampled from a constant ancestral African population of 5,000 effective females. Gray shaded areas indicate P values >0.05.