Ethnic differences in allelic frequencies of two (CA)_n microsatellite markers located on chromosome 5q

Abstract

The characteristics of allelic polymorphisms of the two (CA)n microsatellite (p599 and λ599) markers spanning the long arm of chromosome 5 were studied in 52 DNA samples from unrelated inhabitants of Seoul (Korea) by using the polymerase chain reaction (PCR) to investigate differences in allele frequencies between Korean and Caucasian populations. The 6 alleles were observed for p599 (CA)n with a polymorphism informative content (PIC) value of 0.71 and 9 alleles for λ599 (CA)n with a PIC value of 0.82. The observed heterozygote frequencies of the loci were estimated to 0.730 and 0.846, respectively. Several allele frequencies of two loci showed significant differences between Korean and Caucasian populations. Genotype data from the two loci were consistent with the Hardy‐Weinberg equilibrium by χ² test. Linkage disequilibrium between p599 (CA)n and λ599 (CA)n loci was observed in χ ² test between the observed and expected frequency of allelic association. The probability of matching calculated at each locus was 0.104 for p599 (CA)n and 0.043 for λ599 (CA)n, respectively. These results demonstrate the need to determine population‐specific allele frequency distributions for polymorphic markers when performing genetic linkage studies in racially defined several populations.

Key words:

• Polymerase chain reaction
• Polymorphic information
• Hardy‐Weinberg equilibrium
• Spinal muscular atrophy
• Schizophrenia disorder 1

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