Lecture 5: genetic drift

Question 1

genetic drift

Answer 1

random changes in the frequencies of alleles in a population

Question 2

drift and fixation of an allele

Answer 2

drift causes fixation of an allele at a probability equal to its starting frequency

Question 3

genetic drift fundamentals

Answer 3

drift is unbiased
drift is stronger in smaller populations
drift causes genetic variation to be lost
drift causes populations that are initially identical to become different
an allele can become fixed without natural selection

Question 4

strength of genetic drift

Answer 4

stronger in:
-smaller populations
-populations that fluctuate a lot in size
-populations with larger proportions of non-reproductive individuals
-unequal numbers of reproducing males and females

Question 5

effective population size

Answer 5

the size of an idealized population. measures the strength of genetic drift in a population

Question 6

large Ne

Answer 6

weak drift

Question 7

small Ne

Answer 7

strong drift

Question 8

polymorphism

Answer 8

more than two genotypes in a population

Question 9

founder effect

Answer 9

founding of a new population from a small number of individuals