2. Mary has AB negative blood. Mary’s mom and dad have A positive and B positive blood,
respectively. Tom has A positive blood. Tom’s mom and dad have A negative and B positive blood,
respectively.
a) What is the chance that Tom will be able to successfully give blood to their first child?
Mary must be IAIBdd and Tom must be IAiDd
There progeny would have the following phenotypic segregation: ¼ A+ : ¼ A- : ¼ B+ : 1/8
AB+ : 1/8 AB- : 1/8 B+ : 1/8 BSince Tom has the A and Rh antigens, anyone that produces A or Rh antibodies will reject
his blood. A+ and AB+ can receive his blood. Thus, 3/8 chance that child will be able to
receive his blood
b) What is the chance that Mary will be able to successfully receive blood from their first child?
Mary only has Rh antibodies in her blood. Thus will only reject Rh positive blood.
Thus, A-, B- and AB- can give her blood. Thus, ½ chance she will be able to receive
blood from her child.
4. You are interested in determining the mode of inheritance for a particular trait (earwax
color). You cross two heterozygous individuals and observe the resulting progeny. For each
of the following outcomes, what conclusions should be drawn regarding the mode of
inheritance?
a) You observed a 1 dark : 2 moderate : 1 light phenotypic ratio Incomplete Dominance
b) You observed a 9 dark : 7 light phenotypic ratio Duplicate Recessive Epistasis
6. In jaguars, the dominant allele A causes solid tail color, and the recessive allele a, if expressed, results
in white spots on a colored background. The black coat color allele B is dominant to the brown allele
b, but these genes can only be expressed if the animal has an dd genotype at a third gene. Animals
that are D- are yellow regardless of which allele from the B locus is present. A mating between a
solid yellow-tailed male jaguar and a solid brown-tailed female jaguar produce 20 offspring with the
following tail phenotypes: seven solid yellow, two spotted yellow, three solid black, two spotted
black, four solid brown, and two spotted brown.
a) Which of these three genes, if any, is an epistatic gene? Briefly explain D…controls expression
of B
b) Which of these three genes, if any, is a hypostatic gene? Briefly explain B…only expressed if
correct genotype for D gene exists
c) What are the most likely genotypes of the male and female parents?
Male: AaDdBb
female: Aaddbb
d) What is the probability of the next offspring from these same two parents having a solid brown
tail?
(¾ chance of solid tail) x (1/2x1/2 chance of brown) = 3/16
8. If a man with blood Type B, whose mother was Type O, marries a woman with blood Type
AB, what will be the chance that they have a Type B child?
50%
9. Blood typing has often been used as evidence in paternity cases, when the blood type of the
mother and child may indicate that a man alleged to be the father could not possibly have
fathered the child. For the following mother and child combinations, indicate which genotypes
(and respective blood types) could father the child, and which genotypes would be exonerated.
Blood group
of mother
Blood group
of child
AB
A
O
A
O
B
B
AB
O
A
Father must have one of these
Genotypes
Blood type
A
B
A
A
Geno : I I , I i, I IA, IBi, ii
Man exonerated with one of these
Genotypes
Blood type
B
B
Geno : I I
Pheno: AB, A, B, O
Pheno: none
Geno : IAIB, IBi, IBi
Geno : IAi, IAIA ii
Pheno: AB, B
Pheno: A, O
Geno : IAIB, IBi, IBIB
Geno : IAi, IAIA, ii
Pheno: AB, B
Pheno: A, O
Geno : IAi, IBi, ii
Geno : IAIB, IAIA, IBIB
Pheno: A, B, O
Pheno: AB
Geno : IAIB, IAi, IAIA,
Geno : IBIB, IBi, ii
Pheno: AB, A
Pheno: B, O
10. A woman of blood type AB marries a man of blood group A whose father was type O.
What is the probability that:
a. Their child will be Type A? 1/2
b. Their child will be Type B? 1/4
c. Their child will be Type AB? 1/4
d. Their child will be Type O? 0
11. State whether the child mentioned can actually be produced from the described couple.
Explain your answer
a. An O child from the parents of type A and B. yes, could be IAi x IBi to make ii
b. An O child from the parents of type AB and A no, could be IAIB can not give i
c. An A child from the parents of type AB and B yes, could be IAIB x IBi to make IAi
12. What would happen if a Type A person received blood from:
a. A type B person? Would reject it
b. A type A person? Would accept it
c. A type AB person? Would reject it
d. A type O person? Would accept it
13. Fill in the following table:
14. Suppose that a husband (genotype IAi) and wife (genotype IAIB) have kids.
Kids: ½ Type A : ¼ Type B : ¼ Type AB
a. What is the chance that the father will be able to receive blood from his child? ½ (only
from Type A kids)
b. What is the chance that the child will be able to receive blood from his mother? ¼ (only
the AB kids)
15. Assume that Keith has Type A blood. Keith’s mother was type O. His wife, Sally, has Type
B blood. Her father had type A blood.
a. Write the genotypes of Keith and Sally, if they can be determined. If not, write all
possibilities.
Keith: IAi
Sally: IBi
b. Determine the expected phenotypic segregation of their progeny. 1 AB : 1 A : 1 B : 1 O
c. Which of their kids could donate blood to Keith? Briefly explain your answer. A and O
could give
16. Both Mrs Smith and Mrs Jones had babies the same day in the same hospital. Mrs Smith
took home a baby girl, whom she named Shirley. Mrs Jones took home a baby girl, who she
named Jane. Mrs Jones began to suspect, however, that her child had been accidently
switched with the Smith baby in the nursery. Blood tests were made: Mr Smith was type A,
Mrs Smith was type B, Mr Jones was type A, Mrs Jones was type A, Shirley was type O and
Jane was type B. Had a mixup occurred? Yes, although SHriley could belong to either
couple, Jane must be the child of Mrs Smith in order to get the IB allele. So Shirley and Jane
must have been switched in the hospital