GEOGRAPHY OF EFFECTIVE SIZE IN RURAL POPU LATIONS FROM NORTHERN EURASIA - EFFECTIVE SIZE AND THE RATE OF RANDOM GENETIC DRIFT

On the basis of 655 direct and indirect estimations of effective size (N-e) of rural populations, a map of the geographic distribution of N- e in northern Eurasia was constructed. A geographic dine of N-e was fo und, with its value decreasing by three orders of magnitude from the d irection of southwest (the western Caucasus and Central Asia) to north east (the coasts of the Sea of Okhotsk and the Bering Sea). The area o f highest distribution density of mean N-e values was situated meridio nally between the Ob and Yenisei rivers from the Arctic coast of Taimy r Peninsula to the eastern Sayany and the south Baikal regions. Anothe r similar area covered the south Baltic region, Belarus, and northwest ern Ukraine. The average effective population size in northern Eurasia was N-e = 211.6, the geometrical mean G = 176, the harmonic mean H = 147, and the modal value Mo = 102. These characteristics of effective population size indicate a considerable contribution of stochastic gen e drift to the differentiation of the northern Eurasian gene pool and the geographic dine of the rate of gene drift in the subcontinent. By means of transformation of the N-e map, a map for the rate of stochast ic gene drift (1/4N(e)) in northern Eurasia was obtained.