BIO 123 PROBABILITY AND GENETICS LAB REPORT AND ANSWERS
1. Based on the parents' genotypes, what is the genotypic ratio expected from
a monohybrid cross between the two parents for the trait?
The genotype of both parents is Bb. Hence, after monohybrid cross, the genotype ratio can be
determined as follows:
The F1 generation will have genotype ratio BB:Bb:bb= 1:2:1.
B b
B BB Bb
b Bb bb
2. Based on the genotypic ratio from question 1, what is the expected probability of
each genotype?
25%
BB
50%
Bb
25%
bb
3. Toss the coins together 50 times and keep a tally sheet while doing so. They can only
turn up as BB, Bb, or bb. Remember: each coin represents each parent and each toss can
only turn up one way, therefore, a parent can give only one gene of a pair. How many
tally's for each genotype did you get?
1. BB
2. Bb
3. bb
BB = 15
Bb = 24
bb = 11
1. Based on the parents' genotypes, what is the genotypic ratio expected from
a monohybrid cross between the two parents for the trait?
The genotype of both parents is Bb. Hence, after monohybrid cross, the genotype ratio can be
determined as follows:
The F1 generation will have genotype ratio BB:Bb:bb= 1:2:1.
B b
B BB Bb
b Bb bb
2. Based on the genotypic ratio from question 1, what is the expected probability of
each genotype?
25%
BB
50%
Bb
25%
bb
3. Toss the coins together 50 times and keep a tally sheet while doing so. They can only
turn up as BB, Bb, or bb. Remember: each coin represents each parent and each toss can
only turn up one way, therefore, a parent can give only one gene of a pair. How many
tally's for each genotype did you get?
1. BB
2. Bb
3. bb
BB = 15
Bb = 24
bb = 11
