Y-STR and Mitochondrial DNA: Lineage Analysis and Database Considerations (UGC-NET Unit III)

Advanced UGC-NET Forensic Science Unit III drill on lineage markers: Y-chromosome short tandem repeats (Y-STR) and mitochondrial DNA (mtDNA). Y-STR coverage spans Yfiler Plus 27-locus and PowerPlex Y23 multiplexes, paternal inheritance with no recombination on the non-recombining region of Y (NRY), male-specific typing in sexual-assault casework, haplotype frequency estimation via the Y-chromosome haplotype reference database (YHRD), the counting and discrete laplace methods, inability of standard Y-STRs to resolve paternally related males, and use of rapidly mutating Y-STRs (DYS570, DYS576, DYF387S1). mtDNA coverage includes the 16,569 bp circular genome, the revised Cambridge Reference Sequence (rCRS, Anderson 1981 / Andrews 1999), hypervariable regions HV1, HV2, HV3, Sanger and massively parallel sequencing (MPS) workflows, point and length heteroplasmy, drift across tissues, maternal lineage, haplogroups (M and N for India), application to highly degraded samples (hair shafts, bones, ancient remains), EMPOP and SWGDAM interpretation guidelines, and casework benchmarks including the Romanov identification (Gill et al. 1994). Indian context covers ICMR, CCMB, CDFD, and CFSL DNA divisions.