Gene Mutation, DNA Repair, and Homologous Recombination

These flashcards cover key concepts related to gene mutations, DNA repair processes, and mechanisms of homologous recombination, based on the provided lecture notes.

What is the primary source of genetic variation among individuals?

Genetic mutations.

What is the Luria and Delbrük’s Fluctuation Test used to support?

The random mutation hypothesis.

What are spontaneous mutations?

Mutations that occur naturally and randomly, often related to normal biological processes.

What results from induced mutations?

They arise from external factors, either natural or artificial.

What is the difference between somatic mutations and germline mutations?

Somatic mutations occur in non-germ cells and are not heritable, while germline mutations occur in gametes and can be inherited.

What do regulatory mutations affect?

Regions like promoters, introns, and UTR segments.

What is a promoter mutation?

A mutation that alters the consensus sequence nucleotides of a promoter, affecting transcription initiation.

What are splicing mutations?

Mutations that affect intron/exon boundaries, leading to splicing errors in mRNA.

What is a point mutation?

A mutation that changes a single nucleotide, which can affect an amino acid sequence.

What is a nonsense mutation?

A mutation that changes a codon to a stop codon, prematurely terminating protein synthesis.

What is the function of DNA polymerase during DNA replication?

It accurately inserts nucleotides and proofreads to maintain fidelity.

What are trinucleotide repeat mutations?

Mutations that involve the expansion of sequences of three nucleotides, often leading to diseases.

What is the purpose of nucleotide excision repair?

To repair bulky DNA lesions, particularly UV-induced damage.

What is a Double-Stranded Break (DSB) repair?

A repair mechanism that can lead to translocations if unpaired bases are deleted.

What role does Rad51 play in homologous recombination?

It identifies and binds to double-strand breaks.

What happens during the resolution of a double Holliday junction?

It can lead to either gene recombination or the creation of heteroduplex regions.

What are chemical mutagens and their effect?

Agents that induce mutations by modifying DNA bases, leading to nucleotide mispairing.

What factors induce point mutations?

Natural or artificial mutagens, including chemicals and radiation.