Mixture Interpretation in DNA Analysis

Mixed Biological samples are often encountered in cases like disaster victim identification, sexual assault cases, old excavated remains, physical assault, parentage, dispute for aborted fetus, mass killing etc. In carrying our DNA profiling of such biological materials, presence of multiple markers in each locus is observed, which is generally indicated by multiple peaks of varying heights in the genotype plot. Careful observation and interpretation of such peaks can resolute the degree of mixture to an acceptable value and thus, individualization can be carried out with an accuracy of higher probability value. At times, when alleles are not masked, a minor contributor to the mixed profile may be elucidated. Almost always in a mixture interpretation, certain possible genotypes can be excluded. It may be difficult to be confident regarding the number of contributors in some complex mixtures of more than two individuals; however, the number of contributors often can be inferred by reviewing the data at all loci in a profile. In the current piece of work, an attempt has been made to resolute the contributor individuals in known mixture of blood samples in various proportions, drawn from three unrelated healthy male donors. The techniques and results obtained are discussed in the paper.