Genetics: Multiple Allele Traits - KEY

Blood Type

Blood type is controlled by 3 alleles: A, B, O. A & B are codominant, O is recessive.

1. a) What are the two genotypes possible for a person who as A blood? ____AA, AO___
b) What genotype does a person with AB blood have? ____AB_______
c ) What genotype does a person with O blood have? ____OO______
d) What are the two genotypes possible for a person who as B blood? ______BB, BO_____

2. A man with type AB blood is married to a woman also with type AB blood. What percentage of their children will have:
A blood? ___25%___ B blood? _25%___ O blood _0%____ AB blood _50%______

3. A man has type B blood (genotype BB) is married to a woman with type O blood. What blood type will all their children have? ____B___ What is the genotype of the children? __BO____

4. A woman with type A blood (genotype AO) is married to a type B person (genotype BO). What proportion of their children will have:
A blood? __25%____ B blood? __25%___ O blood __25%__ AB blood __25%_____

5. A woman with type A blood is claiming that a man with type AB blood is the father of her child who is type B.
Could this man be the father of the child? ___yes_________ Show the possible crosses; remember that the woman can have AA or AO genotypes.
Assuming that he is the father, what must the mother's genotype be? _AO_

6. A man with type AB blood is married to a woman with type O blood. They have two natural children and one adopted child. Jane has type A blood, Bobby has type B blood, and Grace has type O blood. Which child was adopted? _____Grace_______

SMILEYS GENETICS -

Teacher's note- students may have less trouble with these if you tell them to assign them letters like blood type letter, A, B, and O

7. Show Genotypes

files..................SS...............................SD......................DD.................................OO.................

8. If a star-eyed smiley (homozygous) is crossed with a dot-eyed smiley (also homozygous) what will all of their offspring look like?

SS x DD , all offspring SD


9. If the pair in the cross above were both heterozygous, what percentage of the offspring will be: SD x SD
Starry __25%__ Star-dot _50%____ Dot __25%_ Square __0%__

10. If a starry-dot eyed smiley is crossed with a square eyed smiley what percentage of the offspring will be:
Starry _50%___ Star-dot ______ Dot __50%__ Square ____

11. If two starry-dot eyes smileys are crossed, what percentage of the offspring will be:
Starry _25%___ Star-dot __50%__ Dot _25%___ Square _0%__

SUNNY GENETICS

smiles

Determine the genotypes of the following Sunnys. It is a multiple allele trait, spiked and circles are codominant and the bare trait is recessive.

12. Show genotypes: SS, SC, CC, OO

13. If a spiked sunny (heterozygous) is crossed with a bare sunny, what percentage of the offspring will be bare? ___50%______
What percentage will be spiked? ___50%______

14. If a spike-circle sunny is crossed with a heterozygous spike sunny, how many of the offspring will be spiked? ___50%__
How many will be circles? ___25%_______
How many will be spike-circles? _______25%______

15. A female sunny who is spiked is married to a male sunny who is circle. They have a child who is bare. What must be the genotypes of the two parents? ___SO x CO_____________