Skip to content
Login Register

#nucleotide addition

2 public questions tagged with this topic.

RDT Basics

Terminal transferase adds nucleotides at:

Terminal deoxynucleotidyl transferase, also called TdT, is a unique template-independent DNA polymerase expressed in pre-B and pre-T lymphocytes where it adds N-nucleotides during V(D)J recombination. In vitro, it catalyzes addition of deoxyribonucleotides preferentially to the 3'-hydroxyl terminus of single or double-stranded DNA, extending the strand without a complementary template. This property underlies homopolymer tailing for cDNA cloning, 3'-end labeling with dideoxynucleotides, and generation of sticky ends from blunt fragments, as poly-A and poly-T tails can anneal to facilitate reco

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
Gene Tar getting

What kind of mutation is produced if one allele has a nucleotide addition and the other a deletion?

CRISPR editing of diploid mammalian cells can affect zero, one or both alleles. When Cas9 induces double strand breaks independently repaired by non-homologous end joining, distinct indel signatures arise per allele. If one chromosome acquires a single base insertion causing frameshift and homologous chromosome acquires base deletion at same locus, alleles carry different mutations yet both disrupted. This state is termed biallelic heterozygous or compound heterozygous mutant, differing from homozygous where both alleles share identical alteration and monoallelic where only one allele mutated.

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