7/ tetrad analysis

Question 1

permissive and selective conditions for s cerevisiae

Answer 1

• permissive - complete media, or ideal s cerevisiae growing temp of 28 C, mutants and wt
• selective - minimal media, temp of 36C - mutant proteins cant fold properly, wt only

Question 2

2 linked genes - parental ditype

Answer 2

• all 4 products of meiosis are the same as one of the parents

Question 3

2 unlinked genes (independent assortment) - non-parental ditype vs parental ditype

Answer 3

• 50% of the time: all parental genotypes - parental ditype
• other 50%: non parental genotypes - non-parental ditype

Question 4

whats a tetratype, what gives a tetratype, what does this not tell us about

Answer 4

• 2 parental and 2 non parental genotypes - 4 dif products
• single crossover between 2 loosely linked genes OR single crossover between a gene and its centromere on unlinked genes
• doesn’t tell us about linkage

Question 5

what do you conclude if you see lots more parental ditypes than non pds

Answer 5

genes are linked

Question 6

what do you conclude if there are the same number of pd and non pd

Answer 6

genes are unlinked