Pedigrees

Study the pedigree above and answer the following questions:

After you have found your answer, you can check it to see if you are right by clicking on the question marks "???".

1.  Who is affected by the hereditary condition? ??? Henry is affected

2.  Who is Daniel's wife? ??? Celia is Daniel's wife

3.  Who is Ivy's sister? ??? Gail is Ivy's sister

4.  Who is Gail's cousin? ??? John is Gail's cousin

5.  Who are John's grandparents?  ??? Alice and Benjamin

6.  Who is Henry's uncle? ??? Frederick is Henry's uncle

Example 2

Albinism is caused by a recessive gene.  Let's call the allele a and the allele for pigmented skin A. 

1..  What is the genotype of the woman in generation I?  ??? genotype = aa

2.  How many children did she have?  How many boys? How many girls?  ??? 3 kids - 2 girls and 1 boy

3.  What are the genotypes of each of her children?  ??? all are Aa

4.  Were any of her grandchildren born albino (that is to say generation III)?  ??? no there are no albinos in generation III

5.  Based on the information shown for generations before and after, give the genotypes of the following people:

• the genotype of person P  ??? genotype = Aa

• the genotype of person Q  ??? genotype = Aa

• the genotype of person X  ??? genotype = Aa

• the genotype of person Y  ??? genotype = Aa

6.  What is the genotype of all the people in generation IV who have darkend shapes (who are affected?)  ??? aa

Example 3

Night blindness is a dominant trait.  Individuals who are affected have trouble seeing in low light.  Let's call the allele N for night blindness and n for normal vision.

1.  What is the genotype of person 1? ??? Nn

2.  What is the genotype of person 5? ??? Nn

3.  Is it possible to know the genotype of person 8? ??? Yes it is Nn

4.  What is the genotype of person 10? ??? Nn

5.  Could 13 be NN? Explain.  ??? No because one parent is nn

6.  What is the genotype of person 15? ??? Nn