Abstract:
new 16 X-short tandem repeat (STR) multiplex PCR system has recently been developed for Sr
Lankans, though its applicability in evolutionary genetics and forensic investigations has not been
thoroughly assessed. In this study, 838 unrelated individuals covering all four major ethnic groups
(Sinhalese, Sri Lankan Tamils, Indian Tamils and Moors) in Sri Lanka were successfully genotyped
using this new multiplex system. The results indicated a high forensic efficiency for the tested loci in
all four ethnicities confirming its suitability for forensic applications of Sri Lankans. Allele frequency
distribution of Indian Tamils showed subtle but statistically significant differences from those of
Sinhalese and Moors, in contrast to frequency distributions previously reported for autosomal STR
alleles. This suggest a sex biased demographic history among Sri Lankans requiring a separate
X-STR allele frequency database for Indian Tamils. Substantial differences observed in the patterns
of LD among the four groups demand the use of a separate haplotype frequency databases for
each individual ethnicity. When analysed together with other 14 world populations, all Sri Lankan
ethnicities except Indian Tamils clustered closely with populations from Indian Bhil tribe, Bangladesh
and Europe reflecting their shared Indo-Aryan ancestry.
