Complex Systems Laboratory, Universitat de Girona, C/Maria Aurèlia Capmany 61, 17003, Girona, Catalonia, Spain.
Catalan Institution for Research and Advanced Studies (ICREA), Passeig Lluís Companys 3, 08010, Barcelona, Catalonia, Spain.
Sci Rep. 2017 Sep 11;7(1):11229. doi: 10.1038/s41598-017-11629-8.
Using a database with the mitochondrial DNA (mtDNA) of 513 Neolithic individuals, we quantify the space-time variation of the frequency of haplogroup K, previously proposed as a relevant Neolithic marker. We compare these data to simulations, based on a mathematical model in which a Neolithic population spreads from Syria to Anatolia and Europe, possibly interbreeding with Mesolithic individuals (who lack haplogroup K) and/or teaching farming to them. Both the data and the simulations show that the percentage of haplogroup K (%K) decreases with increasing distance from Syria and that, in each region, the %K tends to decrease with increasing time after the arrival of farming. Both the model and the data display a local minimum of the genetic cline, and for the same Neolithic regional culture (Sweden). Comparing the observed ancient cline of haplogroup K to the simulation results reveals that about 98% of farmers were not involved in interbreeding neither acculturation (cultural diffusion). Therefore, cultural diffusion involved only a tiny fraction (about 2%) of farmers and, in this sense, the most relevant process in the spread of the Neolithic in Europe was demic diffusion (i.e., the dispersal of farmers), as opposed to cultural diffusion (i.e., the incorporation of hunter-gatherers).
利用一个包含 513 名新石器时代个体的线粒体 DNA (mtDNA) 的数据库，我们量化了单倍群 K 频率的时空变化，此前该单倍群被提出作为一个相关的新石器时代标记。我们将这些数据与模拟结果进行了比较，模拟结果基于一个数学模型，该模型假设新石器时代的人口从叙利亚扩散到安纳托利亚和欧洲，可能与中石器时代的个体（他们缺乏单倍群 K）杂交，或者向他们传授农业。数据和模拟都表明，单倍群 K 的百分比（%K）随着与叙利亚距离的增加而减少，并且在每个地区，%K 在农业到来后的时间增加时趋于减少。模型和数据都显示了遗传渐变的局部最小值，并且对于相同的新石器时代区域文化（瑞典），观察到的单倍群 K 的古老渐变与模拟结果一致，表明大约 98%的农民没有参与杂交也没有受到文化融合（文化扩散）的影响。因此，文化融合只涉及了一小部分（约 2%）的农民，在这个意义上，新石器时代在欧洲传播的最相关过程是人口扩散（即农民的分散），而不是文化融合（即采集狩猎者的融入）。
