I am totally lost when it comes to genotypes and phenotypes... help with these problems?

Question

A teenage girl gets pregnant and won’t tell her parents who the father is. Her parents contact the parents of all the boys she has dated in the last year to find out their blood types. The daughter has blood type O and the baby has blood type A. Boyfriend #1 has type B blood, Boyfriend #2 has type O blood, Boyfriend #3 has type AB blood.

Who should the parents point their shotgun at, and what are the genotypes of the individuals at the alter (including the baby)? Use the following alleles: A, B, i

The father is:

Genotypes

Mom

Dad

Baby

5. The number of horns in jackalopes follows the rules for incomplete dominance. Alleles are H = 2 horns, h = 0 horns. If a jackalope that has 2 horns is crossed with a jackalope that has no horns, how many horns will their offspring have? Give the genotype(s) and phenotype(s) for their offspring.

Answer 1

Firstly human blood type is an example of co-dominance ( where there are 2 dominant alleles A and B with i ( sometimes written as O) is recessive.

The genotypes and phenotypes are as follows:

AA and Ai are A blood type

BB and Bi are B blood type

AB is AB blood type

ii= O blood type

THe girl ( ii) and the child is A blood type. THe genotpyes could be AA or Ai....as the mother isO (ii) she MUST pass on one i allele to the child so the genotype of the child is Ai.

THe father MUST pass on the A allele so he will either be an A ( either AA or Ai) OR AB blood type.

boyfriends 1 and 2 are B and O which are not able to be the father so bf 3 seems the likely culpret ( AB).

for your other question

Incomplete dominance is where you will get a blend of parental characters.

HH = 2 horns

hh= 0 horns

As it is usually somewhere half between i assume Hh will be 1 horn.

hope this helps

  

Answer 2

Boyfriend #3 is the baby daddy.  Type O blood is recessive, which means that the genotype for mom is OO.  Boyfriend #1 has a genotype of either BB or BO, either way can't father a type A baby.  Boyfriend #2 has type O, so his genotype is OO, also can't father the baby.  Boyfriend #3 is AB, so his genotype is AB, meaning a baby fathered with a type O mother would either have type A or type B blood.  Since he is the only boyfriend with an A in his genotype, he must be the father.  So:

Mom=OO

Dad=AB

Baby=AO

The other question-I assume that a jackalope with two horns must have a genotype of HH, and a jackalope with no horns must have a hh genotype.  So if you do a punnet square with those, all the offspring have a genotype of Hh, and would presumably have 1 horn.

I hope that helps you.