The outward appearance of living organism that can be visualized is known as External visible characteristic (EVCs). These are related to the interaction of different genes among themselves and with their environment. Through this technique police investigators or other forensic investigators determine perpetrators which are completely unknown to investigating authourities or to pinpoint missing persons utilizing biological samples in those situations where all other evidences of query, along with conventional DNA profiling give non-uniformities. Eye color is a multiplex trait controlled by many genes but the two major genes which play crucial role to determine eye color are OCA2 and HERC2 genes. 74% eye color of human is under the control of OCA2 gene and its function is influenced by HERC2 gene. These are present on chromosome 15. Eye color trait has miscellaneous inheritance pattern which does not obey simple pattern of Mendelian inheritance.
Blood samples of 40 volunteers along with photographs of iris collected from local population of Pakistan by categorizing different eye colors. DNA was extracted using organic extraction method. Then amplified using PCR with primers of SNP rs1800401 of OCA2 gene and SNP rs12913832 of HERC2 gene. Primers were designed through primer 3 software. Amplicons were analyzed by gel electrophoresis. Samples were sequenced by Sanger sequencing and chromatograms were analyzed by pairwise and multiple alignment tools.
We mapped five polymorphic sites in OCA2 gene including SNPs rs1800401 and rs10300271. Polymorphic sites of OCA2 are 89406 C>T, 89401 G>T, 894019 A>T, 89422 A>C and 89435 C>A. Six polymorphic sites of HERC2 also analyzed including SNP rs12913832 at 206678 T>C and other polymorphic sites are 206617delA, 206631delA, 206683 T>A, 206688delA and 206713delA. These polymorphic sites were further analyzed by applying t-test which shows no significant association between retrieved polymorphic sites and eye color except polymorphic site 89422 with genotype A>C in OCA2 gene (novel) and polymorphic site 206678 with genotype T>C in HERC2 gene (already reported) both are associated with non-brown eye color variation in our study. In conclusion, more research to DNA based human appearance prediction is recommended using large sample size as there are more SNPs also involve that would be very useful for identification or investigative leads in forensic future aspects.