Question

There are two types of twins, monozygotic (identical) twins where the offspring are generated from the unexpected splitting of the same fertilised egg, while dizygotic (fraternal) twins arise from independent fertilisations of two different eggs. Discuss the power of STR profiling in discriminating between monozygotic and dizygotic twins [2-3 sentences].

Answer 1

Short Tandem Repeats (STR) are repetitive DNA segments found in the genome. They are present at thousands of locations in the genome. Also known as microsatellites. These are used extensively in forensic analysis, known as STR profiling. This technique is used to differentiate and compare alleles at different loci in DNA within two or more samples.

Twin zygosity can be determined by STR profiling these days ( whether twins are monozygotic or dizygotic). By analysing the polymorphic loci of STR, amplifying and then comparing to reference samples; origin of vells or tissues can be identified. This is not much useful in determining monozygotic twins because they have same genetic material, minimising other genetic effects.

Refer to this paper : https://pubmed.ncbi.nlm.nih.gov/16772284/

https://www.sciencedirect.com/science/article/pii/S1872497313002275