DNA and Mitochondrial DNA

Mitochondrial DNA (mtDNA)

DNA located in mitochondria, distinct from genomic DNA, involved in cellular energy production and inherited maternally.

Benefit of mtDNA in forensics

Greater sensitivity in degraded or small samples due to higher abundance compared to nuclear DNA.

Limitation of mtDNA in forensics

Lower discriminatory power because mtDNA is maternally inherited and identical among maternal relatives.

Features of mtDNA

Contains approximately 16,500 base pairs, 37 genes, and is circular in structure.

Inheritance Pattern of mtDNA

Strictly maternal; inherited only from the mother to children.

Analysis of mtDNA sequence

Focuses on hypervariable regions, particularly the D-loop, which allows differentiation between individuals.

Applications of mtDNA in forensics

Used for identifying remains, maternal lineage tracking, and when nuclear DNA is not available.

VNTR DNA profiling process

Involves DNA isolation, restriction enzyme digestion, gel electrophoresis, Southern blotting, and detection.

Limitations of VNTR analysis vs. STR analysis

Requires larger DNA samples, is time-consuming, less precise, and difficult with multiple alleles.

Process of STR DNA profiling

Involves DNA extraction, amplification of STR regions using PCR, analysis of PCR products, and creation of an electropherogram.

Electropherogram

Graphical representation of PCR products in STR profiling, showing peaks that correspond to specific STR alleles.

Applications of STR profiling

Used in forensic identification, criminal investigations, paternity testing, and comparison with DNA databases.

Advantages of STR profiling

High discriminatory power, speed, and sensitivity, capable of analyzing small or degraded samples.