Lecture 29

Question 1

How does S. cerevisiae divide?

Answer 1

budding, unequal cytokinesis

Question 2

What are the two mating types of yeast?

Answer 2

a and 𝛼

Question 3

What is meiotic recombination?

Answer 3

any process that generates recombinant gametes or recombinant offspring

Question 4

What are the two combinations that occur during meiotic recombination?

Answer 4

parental: same allele combinations as parents

recombinant types: new allele combinations

Question 5

Why do meiotic recombinations occur?

Answer 5

create new combinations of alleles that give advantage

Question 6

What happens when genes are on different chromosomes?

Answer 6

meiosis I, homologous pairs line up randomly at metaphase I, 2 orientations possible, produces recombinant combinations even without crossing over

Interchromosomal recombination, explained by independent assortment

GOAL: A/B or a/b

Question 7

What happens when genes are on same chromosomes?

Answer 7

crossing over in prophase I produces new allele combinations

early prophase I -> homologs pair
late prophase I -> crossing over occurs between chromatids

intrachromosomal recombinants made, driven by crossovers

GOAL: A/B or a/b