Genetic structure of a 2,500-year-old human population in China and its spatiotemporal changes.

To examine temporal changes in population genetic structure, we compared the mitochondrial DNA (mtDNA) sequences of three populations that lived in the same location, Linzi, China, in different periods: 2,500 years ago (the Spring-Autumn era), 2,000 years ago (the Han era), and the present day. Two indices were used to compare the genetic differences: the frequency distributions of the radiating haplotype groups and the genetic distances among the populations. The results indicate that the genetic backgrounds of the three populations are distinct from each other. Inconsistent with the geographical distribution, the 2,500-year-old Linzi population showed greater genetic similarity to present-day European populations than to present-day east Asian populations. The 2, 000-year-old Linzi population had features that were intermediate between the present-day European/2,500-year-old Linzi populations and the present-day east Asian populations. These relationships suggest the occurrence of drastic spatiotemporal changes in the genetic structure of Chinese people during the past 2,500 years.