Autosomal Dominant and Recessive Inheritance

Topic: This week you have differentiated autosomal dominant and recessive patterns of inheritance of diseases. The assignment this week is designed to elicit a practical application of this information. For this assignment you will analyze a hypothetical family that has an unusually high occurrence of a hypothetical disease known as “X”. The disease is inherited and follows this pattern: homozygous dominant (XX) and heterozygous (Xx) genotypes provide healthy phenotypes while homozygous recessive (xx) provides the disease phenotype.

Occurrence of the disease in the family is as follows. The grandchildren have all had submitted to DNA sequencing to provide their genotypes. We only know the presence or absence of the disease for the grandparents’ and parents’ generation:

Grandfather (healthy) and Grandmother (disease) had 6 children

Child 1 (Male) died at 12

Child 2 (Female) died 29 from the disease.

Child 3 (Male with disease) married and produced two children

Female Grandchild (Heterozygous)

Female Grandchild (Heterozygous)

Child 4 (Female with disease) married and produced two children

Male Grandchild (Homozygous Dominant)

Female Grandchild (Heterozygous)

Child 5 (Stillborn at 21 weeks)

Child 6 (Female with disease) married and produced two children

Female Grandchild (Homozygous Recessive)

Male Grandchild (Heterozygous)

 

Assignment Expectations:

First, determine if disease “X” follows an autosomal dominant or recessive pattern of inheritance. Second, using any means (including hand drawn if necessary), construct a pedigree of the hypothetical family listed above. Provide as many geneotypes as possible for each member of the family. In many cases you will have to solve the parents genotype based on offspring. You may not be able to determine the genotype of all based on the information provided. For those instances list the possible genotypes.

 

After you have completed the pedigree, create a word document that follows these expectations:

• Length should be 800 words, not including the title and references pages (typed, 12 point font, double spaced).
• Provide a short paragraph that describes how you determined the inheritance pattern of Disease X
• Insert the pedigree as picture above (scanned if necessary). Be sure that the pedigree is easy to read and contains all the pertinent information).
• Provide the genotype (or possible genotypes) for each family member listed above. This can be in a list similar to the presentation of the family history shown at the end of the topic section in this assignment.