Probability and Pedigree Practice Problems

Practice 1. We will review the questions on pp. 1-4-through We will review the questions on pp. 1-4-through We will look at the examples of pedigrees in your lab manual. 2. We will look at the examples of pedigrees in your lab manual. 3. You can try the pedigree/probability problems 1-29 and 1-31 on your own. You will apply the principles reviewed on pp. 1-4 to 1-5 and also have you practice drawing some pedigrees. 3. You can try the pedigree/probability problems 1-29 and 1-31 on your own. You will apply the principles reviewed on pp. 1-4 to 1-5 and also have you practice drawing some pedigrees. Please refer to Dr. Colavito’s homepage for solutions. Please refer to Dr. Colavito’s homepage for solutions.

Begin with page – A) Probability of rolling a “5”= 1/6 – B) Probability of rolling an even number: 1/6 + 1/6 + 1/6 = 1/2

Problem 1 continued 1c) 1/6 x 1/6 x1/6 = 1/216 1c) 1/6 x 1/6 x1/6 = 1/216 1d) 6x(1/216)=1/36 1d) 6x(1/216)=1/36 1e) 1/216 x 6 = 1/36 1e) 1/216 x 6 = 1/36 1f) 1 (any number) x 5/6 x 4/6 = 20/36= 5/9 1f) 1 (any number) x 5/6 x 4/6 = 20/36= 5/9

Problem 2 First identify the probabilities of selecting various colors: First identify the probabilities of selecting various colors: –Jar 1: P (y)= 1/5 P (G) = 4/5 –Jar 2 :P (O) = 2/5 P(G) 3/5 –Jar 3 :P (P) 1/10 P(G) 9/10

Problem 2 A. 1/5 x 2/5 x 1/10 = 2/250 = 1/125 A. 1/5 x 2/5 x 1/10 = 2/250 = 1/125 B. 4/5 x 2/5 x 9/10 = 72/250 B. 4/5 x 2/5 x 9/10 = 72/250 C. 1-(probability of no green skittles, see part A.)= 1-1/125=124/125 C. 1-(probability of no green skittles, see part A.)= 1-1/125=124/125

Problem 2 D. calculate all possible combinations for each container: D. calculate all possible combinations for each container: (4/5 x 3/5 x 1/10) + (4/5 x 2/5 x 9/10) + 1/5 x 3/5 x 9/10) = 111/250 (4/5 x 3/5 x 1/10) + (4/5 x 2/5 x 9/10) + 1/5 x 3/5 x 9/10) = 111/250

Problem 2 E. (2/5 x 1/10 x 4/5) = 8/250= 4/125 E. (2/5 x 1/10 x 4/5) = 8/250= 4/125

Problem 3 Autosomal Dominant A. ¾ A. ¾ B. 4!/3!1! (1/4) 3 (3/4) 1 = 3/64 B. 4!/3!1! (1/4) 3 (3/4) 1 = 3/64 C. ¼ x ¾ x/ ¾ = 9/64 C. ¼ x ¾ x/ ¾ = 9/64 D. 1-(probability that all will have straight little fingers)= 1-(1/4) D. 1-(probability that all will have straight little fingers)= 1-(1/4) 3= 63/64

Problem 4: Autosomal Recessive A. 2/3 A. 2/3 B. 2/3 B. 2/3 Keep in mind the parents of Jessica and Jerry must be heterozygous for in order to have a sibling that has CF. Keep in mind the parents of Jessica and Jerry must be heterozygous for in order to have a sibling that has CF.

Problem 4 C. 2/3 x 2/3 x 1/4 = 1/9 C. 2/3 x 2/3 x 1/4 = 1/9 Remember to refer to your Punnett square and you will see that with heterozygous parents there is ¼ chance of cc. Remember to refer to your Punnett square and you will see that with heterozygous parents there is ¼ chance of cc.

Problem 4 D. 3!/2!1! (1/9) 2 (8/9) 1 = 8/243 D. 3!/2!1! (1/9) 2 (8/9) 1 = 8/243 E. 8/9 x 1/9 x 8/9 = 64/729 E. 8/9 x 1/9 x 8/9 = 64/729

Problem 5: X linked recessive ½ that Polly has the “d” allele ½ that Polly has the “d” allele ½ x ¼ =1/8 ½ x ¼ =1/8 ½ x 3/8 x 1/8 = 3/128 ½ x 3/8 x 1/8 = 3/128 5!/2!3! (1/8)2 (7/8) 3 = 3430/32768 = !/2!3! (1/8)2 (7/8) 3 = 3430/32768 =0.105

Let’s move onto Pedigrees Discuss the pedigrees with your group and determine pattern of inheritance and know why you selected your answers. Discuss the pedigrees with your group and determine pattern of inheritance and know why you selected your answers.

Pedigrees (page 1-26) A. autosomal dominant A. autosomal dominant B. X linked dominant B. X linked dominant C. X linked recessive C. X linked recessive D. autosomal recessive D. autosomal recessive E. X-linked dominant E. X-linked dominant F. Autosomal recessive F. Autosomal recessive G. Autosomal Dominant G. Autosomal Dominant H. X-linked recessive H. X-linked recessive

Practice 1. We have reviewed the questions on pp. 1-4-t-5 1. We have reviewed the questions on pp. 1-4-t-5 2. We have looked at the examples of pedigrees in your lab manual. 2. We have looked at the examples of pedigrees in your lab manual. 3. You can try the pedigree/probability problems 1-32 and 1-33 on your own. You will apply the principles reviewed on pp. 1-4 to 1-5 and also have you practice drawing some pedigrees. 3. You can try the pedigree/probability problems 1-32 and 1-33 on your own. You will apply the principles reviewed on pp. 1-4 to 1-5 and also have you practice drawing some pedigrees. Please refer to Dr. Colavito’s homepage for solutions. Please refer to Dr. Colavito’s homepage for solutions.