Hi, folks!
This is a very interesting paper using nuclear DNA to infer past history of
human evolution that just came out in PNAS. This is the abstract.
Peace
Marcio
Worldwide DNA sequence variation in a 10-kilobase noncoding region on human
chromosome 22
Zhongming Zhao*, Li Jin*, Yun-Xin Fu*, Michele Ramsay, Trefer Jenkins,
Elina Leskinen, Pekka Pamilo, Maria Trexler§, Laszlo Patthy§, Lynn B.
Jorde¶, Sebastian Ramos-Onsins*, Ning Yu, and Wen-Hsiung Li,**
PNAS Vol. 97, Issue 21
Human DNA sequence variation data are useful for studying the origin,
evolution, and demographic history of modern humans and the mechanisms of
maintenance of genetic variability in human populations, and for detecting
linkage association of disease. Here, we report worldwide variation data
from a 10-kilobase noncoding autosomal region. We identified 75 variant
sites in 64 humans (128 sequences) and 463 variant sites among the human,
chimpanzee, and orangutan sequences. Statistical tests suggested that the
region is selectively neutral. The average nucleotide diversity () across
the region was 0.088% among all of the human sequences obtained, 0.085%
among African sequences, and 0.082% among non-African sequences, supporting
the view of a low nucleotide diversity (0.1%) in humans. The
comparable value in non-Africans to that in Africans indicates no severe
bottleneck during the evolution of modern non-Africans; however, the
possibility of a mild bottleneck cannot be excluded because non-Africans
showed considerably fewer variants than Africans. The present and two
previous large data sets all show a strong excess of low frequency variants
in comparison to that expected from an equilibrium population, indicating a
relatively recent population expansion. The mutation rate was estimated to
be 1.15 × 109 per nucleotide per year. Estimates of the long-term effective
population size Ne by various statistical methods were similar to those in
other studies. The age of the most recent common ancestor was estimated to
be 1.29 million years ago among all of the sequences obtained and 634,000
years ago among the non-African sequences, providing the first evidence
from a noncoding autosomal region for ancient human histories, even among
non-Africans.
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