Lecture 10 Autosomal Short Tandem Repeat (STR) Profiling

Autosomal Short Tandem Repeat (STR)

A region of genomic DNA containing an array of short repeating sequences, commonly used in DNA profiling.

Short tandem repeat (STR) characteristics

Regions that vary in the number of repeat units among individuals, typically 100-500 base pairs long.

Core repeat region

Tandemly repeated sequences that make up the main part of an STR.

Flanking regions

Surrounding sequences of the core repeat used for PCR primer binding.

PCR (Polymerase Chain Reaction)

A technique used to amplify specific DNA sequences, commonly applied in STR profiling.

Allele

A variant form of a gene or a sequence at a particular locus.

Tetrameric repeat unit

A type of repeat unit consisting of four nucleotides, commonly found in STRs.

Simple repeats

Identical repeat unit sequences in STR profiling.

Compound repeats

Repeats composed of more than one type of simple repeat.

Complex repeats

Repeats consisting of several clusters of different tandem repeats with intervening sequences.

Null allele

An allele that fails to amplify due to a mutation in the primer binding site.

Stutter

A minor allele peak in electrophoresis representing a shorter or longer repeat unit than the parental allele.

Heterozygote imbalance

A situation where one heterozygote allele presents a larger peak than the other allele in electrophoresis.

Amplification artifacts

Unexpected results or errors that occur during the amplification of DNA, which can affect STR profiling.

Low Copy Number (LCN) DNA

Analysis of very small amounts of DNA (<100 pg), often associated with forensic investigations.

Mixture analysis

The process of interpreting DNA samples containing contributions from multiple individuals.

Point mutations

Nucleotide changes that can affect the length of core repeat and flanking regions, impacting STR results.

Capillary electrophoresis

A method used to separate amplified STR products based on size and charge.