BSC2010 Unit 3 Lecture 5

Nucleotide substitution = ___

point mutation

How do rates of substitution differ?

Pseudogenes (nonfunctional) > synonymous substitutions > nonsynonymous substitutions

Why are nonsynonymous mutations least likely?

Could be deleterious

Synonymous and nonsynonymous substitution rates similar = ___

No selective force

Nonsynonymous substitutions exceed synonymous substitutions = ___

positive selection

Synonymous substitutions exceed nonsynonymous substitutions = ___

purifying selection

Neutral theory

At the molecular level, the majority of variants in most populations are selectively neutral.

Neutral variants accumulate through ___ rather than ___.

genetic drift rather than selective forces

The probability of any allele becoming fixed…

is equal to its frequency in the gene pool in a given generation (in the absence of selection or gene flow).

Rate of mutation equations