A healthy couple had their first child affected by cystic fibrosis. Their next three sons were not affected by this disorder. The couple is expecting another child and wishes to know the probability (odds) that this child will be: Not affected if the three brothers are homozygous dominant. Not affected if three unaffected brothers were determined by DNA typing to be carriers. Not affected if she (he) has one affected and five unaffected sisters. Draw pedigree of the family described in c.

A man and woman are both heterozygous for the recessive allele that causes cystic fibrosis. What is the probability that their first two offspring will have the disorder?

The following pedigree shows the inheritance of Huntington’s disease, a fatal genetic disorder that causes neurodegeneration. Since signs and symptoms usually do not appear until adulthood, many who are carriers may not realize their risk of passing on the disease-causing allele.  The following pedigree represents a family in which some people are affected by Huntington’s disease.   Using just the information on this pedigree, is Huntington’s disease caused by a dominant allele or recessive alleles? What are the genotypes of the grandparents (I-1 and I-2)? What are the genotypes of the parents (II-6 and II-7)? If the parents above have another child, what is the chance that they will be affected by the Hungtington’s disease allele? What are the genotypes of the unaffected children (III-8, 9, 10)? What is the chance that the unaffected children above will pass on a Huntington’s disease allele to their children? What is the genotype of the affected child (III-11)? What is the chance…

Below is a pedigree chart for a family that has a history of Alkaptonuria.   Individuals infected with this condition can have darkened skin, brown urine, and can suffer from joint damage and other complications.  Given this pedigree answer the following questions.   Given the data in the pedigree chart is this genetic condition autosomal dominant or autosomal recessive? What are the genotypes for #1, #2, and #3?  If either of the 4th generation "aa" females were to mate with a homozygous dominant male would any of their offspring illustrate the phenotype?  Why or why not?