Skip to content
Login Register

#short tandem repeats

3 public questions tagged with this topic.

Molecular Marker

STRs are primarily used in:

Short Tandem Repeats exhibit 1-6 bp repeat units with high mutation rates due to strand slippage, creating many alleles per locus and high heterozygosity. This hypervariability, combined with codominant inheritance, low DNA requirement, and amenability to multiplex PCR, makes them exceptionally discriminating for individual identification. Forensic genetics, paternity testing and kinship analysis rely on standardized STR panels such as CODIS loci. STRs are not primary tools for DNA synthesis, sequencing chemistry or protein expression; their power lies in resolving identity and relatedness through polymorphic length variation.

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

View Details
Molecular Marker

In STRs, what varies among individuals?

Short tandem repeats comprise tandem arrays of two to six base pair motifs where individual variation derives from different copy numbers of the repeat unit at a given locus. DNA polymerase slippage during replication expands or contracts repeat tracts, creating alleles differing in length but not in base composition or methylation pattern. Enzyme activity is unrelated to structural polymorphism. Consequently, genotyping relies on measuring fragment length variation through capillary electrophoresis, reflecting inherited differences in repeat number critical for forensics and paternity testing.

Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.

View Details