7 public questions tagged with this topic.
Southern blotting uses complementary DNA probes to detect specific DNA sequences through hybridization.
Ref: NCERT Class 12 Biology Chapter 10: Biotechnology and its Applications Medical Applications - Molecular Diagnosis - PCR ELISA
Immunoprecipitation approaches dissect nucleic acid-protein interactions. Chromatin immunoprecipitation targets DNA bound by proteins in cross-linked chromatin, useful for transcription factors and histones. Co-immunoprecipitation precipitates protein complexes to identify protein-protein partners. Immunoprecipitation of RNA-associated complexes using generic antibodies lacks nucleic acid specificity. RNA immunoprecipitation is dedicated to RNA-binding proteins; cells are cross-linked or used native, lysed, and specific antibody against RNA-binding protein enriches messenger RNAs, micro RNAs,
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.
Determination of the authentic 5 prime end of a transcript requires extension of a labeled primer annealed downstream. In primer extension, reverse transcriptase synthesizes complementary DNA until reaching the extreme 5 prime terminus of messenger RNA, generating product whose length indicates transcriptional start site. Northern blotting estimates size and abundance but lacks nucleotide resolution at ends. S1 mapping provides approximate termini, while 3 prime RACE specifically targets the polyadenylated tail. Therefore, primer extension remains a classical method of choice for high-resoluti
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.
Western blotting is inherently unsuitable for DNA detection because it employs antibodies raised against polypeptide epitopes and conditions optimized for protein immobilization and immunorecognition. DNA molecules lack immunoglobulin recognition sites and are not detected by anti-protein antibodies. Furthermore, no nucleic acid probe hybridization step is incorporated. Compatible DNA analysis methods include native or denaturing polyacrylamide gel electrophoresis stained with ethidium bromide, agarose electrophoresis, denaturing high-performance liquid chromatography separating based on melti
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.
Detection of radioactively labeled DNA fragments relies on emission of beta particles from isotopes such as 32P incorporated at termini. Gel electrophoresis separates fragments by size but does not detect radioactivity itself. Spectrometry and colorimetry measure absorbance or color development for quantification, not spatial band position. Autoradiography places dried gel against photographic film; radioactive decay exposes silver halide crystals producing dark bands corresponding precisely to labeled fragment migration positions. This method provides high sensitivity for low abundance labele
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.
Visualization of specific fragments after end labeling requires selective detection of radioactivity rather than total DNA mass. Ethidium bromide intercalates into all double-stranded DNA and fluoresces under UV, revealing every fragment regardless of label. Spectrophotometry quantifies bulk nucleic acid concentration. Autoradiography exposes X-ray film only where beta particles from incorporated 32P or 35S decay, so only labeled termini appear as dark bands. Gel drying is preparative. Hence autoradiography uniquely allows ordering labeled fragments in classical restriction mapping protocols b
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.
Klenow fragment retains polymerase and 3' to 5' exonuclease but lacks 5' to 3' exonuclease activity, making it ideal for labeling. For end labeling, it fills recessed 3' ends templated by 5' overhangs incorporating alpha-32P labeled nucleotides efficiently. Blunt ends possess recessed 3' terminus after transient breathing and can be labeled by exchange reaction under certain conditions with high deoxynucleotide and enzyme concentrations. While sticky 5' overhangs are preferred substrates for fill-in, blunt-end labeling is classic method to create uniformly labeled probes for restriction mappin
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.
