Co-dominance and incomplete dominance

In humans, straight hair (H^S) and curly hair (H^c) are codominant alleles. Hybrids have wavy hair. What would the genotype and phenotype ratios be if a curly haired female is crossed with a wavy haired male.

In horses, chestnut and white coat colours are codominant. Heterozygous horses end up golden-tan in colour (and are called palomino). 

a.      What would the genotype and phenotype rations be in a cross between a chestnut horse and a white horse?

b.      What would the genotype and phenotype rations be in a cross between a chestnut horse and a palomino horse?

In the 1950’s, a young woman sued Charlie Chaplin for parental support of her illegitimate child. Charlie Chaplin’s blood type was already on record as type AB. The mother was tested and found to be type A, while the child was type O.

a.      Complete a Punnett square for the possible cross of Charlie and the mother.

b.      The judge ruled in favour of the mother and ordered Charlie Chaplin to pay child support. Was the judge correct in his decision based on the blood typing evidence? Justify your answer.

Suppose a newborn baby was accidentally mixed up in the hospital. In an effort to determine the parents of the baby, the blood types of the baby and two sets of parents were determined.

Baby= type O

 

Mrs Brown = type B

Mr Brown = type AB

Mrs Smith= type B

Mr Smith = type B

a.      Draw Punnett squares for each couple (you may need more than one for each couple)

b.      To which parents does the baby belong? Justify your answer.

Study the Punnett square and answer the questions that follow.

 

a)      In pea plants red flowers are dominant to white flowers. What are the genotype and phenotype ratios for the shown cross?

b)      What are the genotypes of the two parents? Explain the parents using terms such as homozygous, heterozygous, dominant, recessive.

A cross between a black chicken and a white chicken produces offspring that are all blue-grey. In domestic chickens black feathers are incompletely dominant to white feathers.

a)      What are the genotypes of the parent chickens in the original cross?

b)      What is/are the genotype(s) of the blue-grey offspring?

c)      What would be the phenotype ratios of offspring produced by two blue-grey chickens?