Y-short tandem repeat haplotype and paternal lineage of the Ezhava population of Kerala, south India.

AIM: To analyze the haplotype of the Ezhava population of Kerala, south India, using 8 short tandem repeat (STR) loci on the Y chromosome and trace the paternal genetic lineage of the population. METHODS: Whole blood samples (n=104) were collected from unrelated healthy men of the Ezhava population over a period of one year from October 2009. Genomic DNA was extracted by salting out method. All samples were genotyped for the 8 Y-STR loci by the AmpFiSTR Y-filer PCR Amplification Kit. The haplotype and allele frequencies were determined by direct counting and analyzed using Arlequin 3.1 software, and molecular variance was calculated with the Y-chromosome haplotype reference database online analysis tool, www.yhrd.org. RESULTS: Among the 104 examined haplotypes, we found 98 unique ones. The average gene diversity was 0.669, with the highest diversity of 0.9462 observed for the biallelic Y-STR marker DYS 385. The allele frequency among DYS loci varied between 0.0096 and 0.75. Out of the 104 haplotypes, 10 were identical to the Jat Sikh population of Punjab, which is the greatest number among the Indian populations, and 4 to the Turkish population, which is the greatest number among the European populations. According to the allele frequency of Y-STR, the Ezhavas were genetically more similar to the Europeans (60%) than to the East Asians (40%). CONCLUSION: The vast majority of haplotypes were observed only once, reflecting the enormous genetic heterogeneity of the Ezhavas. Based on the genotype, the Ezhavas showed more resemblance to Jat Sikh population of Punjab and the Turkish populations than to the East Asians, hence indicating a paternal lineage of European origin.

Detection of Y STR markers of male fetal dna in maternal circulation.

BACKGROUND: Circulating fetal cells and cell free DNA in the maternal blood has been shown to help in prenatal diagnosis of genetic disorders without relying on invasive procedures leading to significant risk of pregnancy loss. AIM: The current study was undertaken to detect the male fetal population using Y STR markers DYS 19, DYS 385 and DYS 392 and also to study the extent of persistence of fetal DNA in the mother following delivery. MATERIALS AND METHODS: Blinded study was conducted on 50 mothers delivering male and female babies. Cellular and cell free DNA was extracted from maternal and fetal cord blood and amplified for Y STR markers by PCR. RESULTS: The amplification sensitivity of Y specific STR, DYS19 was 100% (22/22) in the male fetal DNA samples. The incidence of other STRs, i.e., DYS385 and DYS392 were 91% (20/22) each. Analysis of results revealed that thirteen of the twenty six women had detectable male fetal DNA at the time of delivery. However fetal DNA was not detectable twenty four hours after delivery. CONCLUSION: Preliminary results show that the separation of fetal cell-free DNA in the maternal circulation is a good low-cost approach for the future development of novel strategies to provide non-invasive techniques for early prenatal diagnosis.