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#codon bias

2 public questions tagged with this topic.

MOLECULAR EVOLUTION

Synonymous mutations usually affect:

DNA but not amino acid reflects key principle in quiz on molecular evolution, where evolutionary mechanisms shape genetic variation and adaptation. In this context, DNA but not amino acid aligns with experimental and theoretical evidence from population genetics, behavioral ecology and molecular phylogeny. Textbooks like Campbell Biology, Futuyma Evolution and Hartl Principles illustrate supporting data. Understanding why DNA but not amino acid fits helps integrate natural selection, drift and species concepts essential for NEET, CSIR-NET and GATE examinations. This concept integrates genetics, ecology and molecular evidence, frequently tested in NEET, GATE and CSIR-NET, highlighting links

Ref: Li, Molecular Evolution, Neutral Theory and Molecular Clocks.

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Gene Cloning Process

Why might a eukaryotic protein expressed in E. coli remain non-functional?

Expression of eukaryotic proteins in prokaryotic host Escherichia coli often yields inactive product due to multiple physiological mismatches. Codon bias differs; rare eukaryotic codons cause ribosome stalling, premature termination, and truncation. Prokaryotes lack endoplasmic reticulum machinery for N-glycosylation, disulfide isomerization, and other post-translational modifications essential for stability and activity. Molecular chaperone systems and folding environments also differ, leading to misfolding, aggregation into inclusion bodies, and proteolytic degradation. Combined effects explain multifactorial loss of function requiring eukaryotic hosts or engineered bacterial strains for rescue.

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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