DNA Mutations and Genetic Principles

This set of flashcards covers key terms and definitions related to DNA mutations, mechanisms of mutation repair, principles of genetics, and evolutionary concepts.

Spontaneous mutation

Mutations not caused by environmental factors, but by errors from DNA Polymerase.

Induced mutation

Mutations caused by external agents such as chemicals or radiation.

Somatic mutation

Mutations in somatic cells that are not heritable but can affect cell function.

Germ line mutation

Mutations in gametes that are heritable and can be passed down to offspring.

Point mutation

A mutation where one base is substituted for another without altering the length of DNA.

Transition mutation

A conservative DNA base change between pyrimidines or purines.

Transversion mutation

A nonconservative DNA base change between different types of bases, more rare and potentially lethal.

Silent mutation

A mutation that leads to a different codon but does not alter the corresponding amino acid.

Missense mutation

A mutation that results in a change in a codon and its corresponding amino acid.

Nonsense mutation

A mutation that creates a premature stop codon, terminating protein synthesis.

Loss of function mutation

A mutation that reduces the gene product or biochemical activity of an enzyme.

Gain of function mutation

A mutation that increases the gene product, enzyme activity, or creates a new function.

Null allele

A mutation that prevents the production of any gene product or causes an enzyme to be completely non-functional.

Conditional mutation

A mutation whose expression depends on the environment, like light or temperature.

DNA mismatch repair

A process that fixes errors missed by DNA polymerase involving specific proteins and enzymes.

Base excision repair

A DNA repair mechanism that corrects a single mismatched base.

Nucleotide excision repair

A DNA repair mechanism that repairs multiple base lesions without using a complementary template strand.

Darwin's finches (example of directional selection)

A case where extreme phenotypes, such as beak size, are favored during drought conditions leading to a shift in mean phenotype.

Hardy-Weinberg Equilibrium

A principle that describes expected genotype frequencies based on observed allele frequencies under certain assumptions.

Genetic drift

Random changes in allele frequencies from one generation to the next, especially affecting small populations.