Probability and Probability and Pedigree Practice Pedigree Practice

ProblemsProblems

Pick a cardPick a card

TodayToday

Practice probability problemsPractice probability problems

Practice will help in doing these types of questions.Practice will help in doing these types of questions.

Any problems you do not have time to do, try doing Any problems you do not have time to do, try doing later.later.

Practice Practice

1. Work on the probability problems on 1. Work on the probability problems on pages 1-4 and 1-5 of the lab manualpages 1-4 and 1-5 of the lab manual

2. Pedigrees and probability problems 1-28 2. Pedigrees and probability problems 1-28 and 1-30. These you may need to and 1-30. These you may need to complete at home.complete at home.

Please refer to Dr. Colavito’s homepage for Please refer to Dr. Colavito’s homepage for solutions.solutions.

Begin with page 1-4Begin with page 1-4

1.1.– A) Probability of rolling a “5”= 1/6A) Probability of rolling a “5”= 1/6

– B) Probability of rolling an even number: 1/6 + 1/6 + B) Probability of rolling an even number: 1/6 + 1/6 + 1/6 = 1/21/6 = 1/2

Problem 1 continuedProblem 1 continued 1c) 1/6 x 1/6 x1/6 = 1/2161c) 1/6 x 1/6 x1/6 = 1/216

1d) 6x(1/216)=1/361d) 6x(1/216)=1/36

1e) 1/216 x 6 = 1/361e) 1/216 x 6 = 1/36

1f) 1 (any number) x 5/6 x 4/6 = 20/36= 5/91f) 1 (any number) x 5/6 x 4/6 = 20/36= 5/9

Problem 2Problem 2 First identify the probabilities of selecting First identify the probabilities of selecting

various colors:various colors:– Jar 1: P (y)= 1/5 P (G) = 4/5Jar 1: P (y)= 1/5 P (G) = 4/5– Jar 2 :P (O) = 2/5 P(G) 3/5Jar 2 :P (O) = 2/5 P(G) 3/5– Jar 3 :P (P) 1/10 P(G) 9/10Jar 3 :P (P) 1/10 P(G) 9/10

Problem 2Problem 2

A. 1/5 x 2/5 x 1/10 = 2/250 = 1/125A. 1/5 x 2/5 x 1/10 = 2/250 = 1/125

B. 4/5 x 2/5 x 9/10 = 72/250B. 4/5 x 2/5 x 9/10 = 72/250

C. 1-(probability of no green skittles, see part C. 1-(probability of no green skittles, see part A.)= 1-1/125=124/125A.)= 1-1/125=124/125

Problem 2Problem 2

D. calculate all possible combinations for each D. calculate all possible combinations for each container:container:

((4/5 x 3/54/5 x 3/5 x x 1/101/10) + () + (4/54/5 x x 2/52/5 x x 9/109/10) ) + + 1/51/5 x x 3/5 x 9/103/5 x 9/10) = 111/250) = 111/250

Problem 2Problem 2

E. (E. (2/52/5 x x 1/101/10 x x 4/54/5) = 8/250= 4/125) = 8/250= 4/125

Problem 3 Autosomal Problem 3 Autosomal DominantDominant

A. ¾A. ¾

B. 4!/3!1! (1/4)B. 4!/3!1! (1/4)33 (3/4) (3/4)11= 3/64= 3/64

C. ¼ x ¾ x/ ¾ = 9/64C. ¼ x ¾ x/ ¾ = 9/64

D. 1-(probability that all will have straight little D. 1-(probability that all will have straight little fingers)= 1-(1/4) fingers)= 1-(1/4) 3= 63/64

Problem 4: Autosomal Problem 4: Autosomal RecessiveRecessive

A. 2/3A. 2/3

B. 2/3B. 2/3

Keep in mind the parents of Jessica and Jerry Keep in mind the parents of Jessica and Jerry must be heterozygous for in order to have a must be heterozygous for in order to have a sibling that has CF.sibling that has CF.

Problem 4Problem 4

C. 2/3 x 2/3 x 1/4 = 1/9C. 2/3 x 2/3 x 1/4 = 1/9

Remember to refer to your Punnett Remember to refer to your Punnett square and you will see that with square and you will see that with heterozygous parents there is ¼ heterozygous parents there is ¼ chance of cc.chance of cc.

Problem 4Problem 4

D. 3!/2!1! (1/9)D. 3!/2!1! (1/9)22 (8/9) (8/9)11 = 8/243 = 8/243

E. 8/9 x 1/9 x 8/9 = 64/729E. 8/9 x 1/9 x 8/9 = 64/729

Problem 5: X linked Problem 5: X linked recessiverecessive

½ that Polly has the “d” allele½ that Polly has the “d” allele

½ x ¼ =1/8½ x ¼ =1/8

½ x 3/8 x 1/8 = 3/128½ x 3/8 x 1/8 = 3/128

5!/2!3! (1/8)2 (7/8) 3 = 3430/32768 =0.1055!/2!3! (1/8)2 (7/8) 3 = 3430/32768 =0.105

Pedigrees (page 1-26)Pedigrees (page 1-26)

A. autosomal dominantA. autosomal dominant B. X linked dominantB. X linked dominant C. X linked recessiveC. X linked recessive D. autosomal recessiveD. autosomal recessive E. X-linked dominantE. X-linked dominant F. Autosomal recessiveF. Autosomal recessive G. Autosomal DominantG. Autosomal Dominant H. X-linked recessiveH. X-linked recessive

AnswersAnswers

Check Dr. Colavito’s Check Dr. Colavito’s homepage “study guide” homepage “study guide” to check your answers.to check your answers.