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#DNA mobility

2 public questions tagged with this topic.

Transposable elements

Transposable element mobilization can cause

Mobilization of transposable elements impacts genome through multiple mechanisms: insertion into coding exons disrupts open reading frame causing gene inactivation and null alleles, insertion into introns or near enhancers modulates transcription by providing promoters, splice sites, or insulators altering expression patterns, and transposition intermediates create double-strand breaks that trigger illegitimate recombination leading to deletions, inversions, or translocations. Collectively these effects explain why host silencing via piRNAs, siRNAs, and heterochromatin repression is essential for maintaining stability while permitting evolutionary innovation. This principle illustrates essential molecular mechanisms governing replication fidelity and mutation fixation relevant for exam interpretation.

Ref: Watson et al., Molecular Biology of the Gene, 7th ed., Chapter 12: Functional Consequences of TE Mobilization

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Transcript analysis

In EMSA, slower mobility of DNA indicates:

In EMSA, labeled DNA probe is subjected to non-denaturing gel electrophoresis maintaining native complexes. Free unbound DNA, being small and highly negatively charged, migrates rapidly toward positive electrode, appearing near bottom of autoradiogram. When sequence-specific DNA-binding protein present, DNA engages in stable nucleoprotein complex with substantially larger hydrodynamic radius and altered charge-to-mass ratio. Consequently, electrophoretic mobility is retarded, complex migrates slower and appears as higher band. Intensity and position of retarded band reflect affinity, stoichiometry, and specificity of interaction, which can be confirmed by competition with unlabeled cold probe.

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.

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