"Draw a pedigree for hitchhiker’s thumb. Your pedigree should cover at least two generations and include both dominant and recessive forms of the trait. Label the pedigree with genotypes, using the letter H to represent the dominant allele for the trait and the letter h to represent the recessive allele." I'm confused on the part about having two generations. How do I set up the pedigree?

Answer and Explanation:

First, you need to know how to interpret a pedigree representation.

→ Individuals are represented with geometrical figures.

→ Males are squares

→ Females are circles

→ Healthy/normal/not affected  individuals are represented with empty figures

→ Affected/mutated individuals are represented with solid black figures

→ Each file is represented with a roman number, indicating the Generation.

Now, what we need to do is to draw a pedigree for a hitchhiker’s thumb. We know that this is an autosomal dominant trait, which we will represent with an H. No hitchhiker's thumb is the recessive trait, and it will be represented with an h.

Our pedigree should cover at least two generations and include both dominant and recessive forms of the trait.    

The representation would be like following,

I → First-generation: First cross

II → Second-Generation: F1 and second crosses

III → Third-Generation:

You will find this pedigree in the attached files. In this example, we included three generations. The first one belongs to the grandparents, the second one to parents, aunts/uncles, and the third one to grandchildren.  

If you draw another pedigree, remember to include

1 digestive system

2 stomach

3 bladder

4 carbon deoxide

5 tiger

the correct answer is b