Low variability of the POLG (CAG)n repeat in north Eurasian populations.
Hum Biol
; 77(3): 355-65, 2005 Jun.
Article
in En
| MEDLINE
| ID: mdl-16392637
ABSTRACT
We investigated the frequency of different repeat-length alleles of the trinucleotide CAG microsatellite repeat in the coding sequence of the nuclear gene for the catalytic subunit of mitochondrial DNA polymerase gamma (POLG) in 12 ethnic groups from northern Eurasia. The population sample consisted of 1,330 individuals from 3 large geographic areas Europe, Southwest Asia, and Siberia/East Asia. We found that the 10-repeat allele of the POLG gene is the most frequent in all analyzed populations, with a frequency of 88-96%. The heterozygosity level ranges from 22% in Europe to 13.6% in Southwest Asia with the lowest value of 7.4% in Siberia/East Asia. The present study provides evidence of clinal distribution of POLG gene heterozygosity in North Eurasian populations. In general, we found an extremely low variability of the trinucleotide CAG microsatellite repeat, suggesting that purifying selection acts against deleterious alleles, although low mutability of the repeated region cannot be ruled out.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Genetic Variation
/
DNA, Mitochondrial
/
Tandem Repeat Sequences
/
DNA-Directed DNA Polymerase
/
Genotype
Limits:
Humans
Country/Region as subject:
Asia
/
Europa
Language:
En
Journal:
Hum Biol
Year:
2005
Type:
Article
Affiliation country:
RUSSIA