5 public questions tagged with this topic.
VNTR stands for Variable Number of Tandem Repeats, which are used in DNA fingerprinting due to their high polymorphism. This follows from NCERT principle where the relation explains the outcome clearly for students in simple steps.
Ref: NCERT Biology Textbook for Class XI and XII (Botany section), Chapter: Morphology and Anatomy of Flowering Plants, Topic: Plant structure and tissue systems.
Random Amplified Polymorphic DNA employs single decamer arbitrary primers to amplify random genomic segments without prior sequence information using low stringency PCR annealing at 36°C. Amplified fragments present as bands indicate primer binding sites present in both orientations within amplifiable distance; absence indicates sequence divergence or insertion preventing amplification. Since technique detects presence versus absence of dominant allele but cannot distinguish heterozygous Aa from homozygous dominant AA, both produce band, it behaves as dominant marker with 3:1 segregation. More
Ref: Williams JGK et al. 1990 Nucleic Acids Res – RAPD dominant reproducible issues; Welsh & McClelland 1990
DNA fingerprinting analyzes variations in repetitive DNA sequences, such as VNTRs, to identify individuals.
Ref: NCERT Class 12 Biology Chapter 5: Molecular Basis of Inheritance Human Genome Project and DNA Fingerprinting
Amplified fragment length polymorphism involves sequential steps of complete genomic DNA digestion with rare and frequent cutting enzymes, ligation of double-stranded adapters to fragment ends, pre-selective amplification with primers having one selective nucleotide, followed by selective amplification with primers containing two or three additional selective nucleotides labeled for detection. This two-step PCR reduces complexity and increases specificity, generating fifty to one hundred scorable bands per reaction. Random primer methods or single-step protocols lack this nested selectivity an
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.
Simple sequence repeats exhibit exceptional polymorphism due to high mutation rates caused by slipped-strand mispairing during DNA replication. Variable repeat numbers generate many alleles per locus, often exceeding ten in diverse germplasm, providing high polymorphic information content and heterozygosity values. Their codominant, multiallelic nature surpasses biallelic SNPs, low polymorphism RFLPs and dominant RAPD markers that detect fewer loci. Widespread genomic distribution, excellent reproducibility and ease of PCR detection further enhance utility for linkage mapping, population struc
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.
