Zygosity Test of Twin Pairs Using 26 STR Loci in the Indonesian Population

Background: Twin research can play an important role in understanding the interplay between genes and environment. Classifying twins as monozygotic (identical) or dizygotic (fraternal) is an essential first step in conducting research that will yield valid and replicable findings. Identical twins (theoretically) share 100% of their genes, while fraternal twins share, on average, 50% of their genes.1 This study aims to determine zygosity in 12 twins with Non-Syndromic Cleft Lip and Palate (NSCLP) discordant, concordant, and non-NSCLP.Material and Methods: Blood samples from 12 twin pairs, which include of 8 twins Non-syndromic Cleft Lip and Palate (NSCLP) discordant, 2 twins NSCLP concordant, and 2 twins non-cleft (normal). DNA extraction was using Promega Kit and quantified was using Nano drops. DNA amplification was by PCR with 26 loci, which was packaged in Powerplex Fusion 6C Kit. PCR products were sequenced using ABI3500 and the visualization can be seen using Genemapper TM ID-X 1.6 software.Results: The results show that each pair of 11 twins have a similar alleles in 26 STR loci, which means they are monozygotic twins. Only 1 twin has a different alleles in 10 STR loci, which means they are dizygote.Conclusion: Zygosity tests on MZ twins using STR loci has high similarity and sensitivity. This test would be more accurate by analyzing a higher number of STR loci.