The origin and demographic history of
the ethnic populations of China have not been clearly
resolved. In this study, we examined the hypervariable
segment I sequences (HVSI) of the mitochondrial DNA
control region in 372 individuals from nine Chinese populations
and one northern Thai population. A relatively
high percentage of individuals was found to share sequences
with those from other populations of the same
ethnogenesis. In general, the populations of southern or
Pai-Yuei tribal origin showed high haplotype diversity
and nucleotide diversity compared with the populations of
northern or Di-Qiang tribal origin. Mismatch distributions
from these populations showed concordant features.
All except the northern groups Nu, Lisu, Tibetan, and
Mongolian showed typical signatures of ancient population
expansions in the mismatch distributions and neutrality
tests. Episodes of extreme size reduction in the past
are one of the likely explanations for the absence of evidence
of expansion in northern populations. Small sample
sizes as well as samples from isolated subpopulations
contributed to the bumpy mismatch distributions observed.
Phylogenetic analysis and haplotype sharing
among populations suggest that current mtDNA variation
in these ethnic populations could reveal their ethnohistory
to some extent, but in general, linguistic and geographic
classifications of the populations did not agree well with
classification by mtDNA variation.