D1.3 Gene Editing and Mutations

In what way are mutations "random"?

They cannot be predicted or directed by the organism.

What are "hotspots" in DNA?

Regions more prone to mutation due to sequence repeats or base instability.

What determines if a mutation's consequences are harmful, neutral, or beneficial?

The environment (not the intention of the organism).

What is the evolutionary significance of random mutations?

They provide the raw material for natural selection and evolution.

What is the definition of a gene mutation?

A permanent change in the DNA base sequence that may alter protein structure or function.

What occurs during a Substitution mutation?

One base is replaced by another, affecting only one codon.

What occurs during an Insertion mutation?

One or more bases are added to the sequence, often causing a frameshift.

What occurs during a Deletion mutation?

One or more bases are removed from the sequence, often causing a frameshift.

Which mutation type is generally less disruptive: Substitutions or Indels?

Substitutions (insertions and deletions often cause frameshifts that affect the entire protein).

What is a Silent mutation?

A base substitution that results in no amino acid change due to the degeneracy of the genetic code.

What is a Missense mutation?

A base substitution that results in a different amino acid being coded for, potentially altering the protein.

What is a Nonsense mutation?

A base substitution that creates a premature stop codon, leading to a truncated (shortened) protein.

What is the real-world example of a base substitution mentioned in the notes?

Sickle cell anemia (a substitution in β-globin changing Glu → Val).

Where do Germ cell mutations occur and what is their impact?

They occur in gametes; they are inherited by offspring and passed to future generations.

What do germ cell mutations create in a population?

New alleles, which lead to genetic diseases or variation.

Where do Somatic cell mutations occur and what is their impact?

They occur in body cells; they affect only the individual and are not inherited.

Somatic cell mutations are specifically linked to what disease?

Cancer (if cell cycle genes are disrupted).

What is a "Common Mistake" regarding the inheritance of mutations?

Thinking all mutations are inherited; in reality, only germline mutations are passed down.