Human Genetics Quiz #6 (and last!) November 25, 1996

1. Define "genetic load". What is the estimated genetic load (quantitatively) for humans?

2. What is a trinucleotide repeat and how do they cause mutations?

3. Explain 2 ways a mutation can have a dominant effect.

4. What lod score is sufficient to prove linkage? What lod score is sufficient to prove there is no linkage?

5. If an offspring is formed from one parental gamete and one recombinant gamete, what is the equation that defines the probability of this offspring in terms of the RF (recombination fraction)?

6. What is the term of the multinomial distribution that describes the probability of a family with 3 red offspring, 4 pink offspring, and 2 white offspring, where the expected probabilities are 0.25 for red, 0.50 for pink, and 0.25 for white? (Just write the expression--don't work it out.)

7. Monozygotic twins are formed from a single zygote and thus should be genetically identical. Give 3 reasons why MZ twins might not be phenotypically identical.

8. What is a "meristic" trait? What is a "threshold" trait?

9. What is the rationale for doing an adoption study to prove that there is a genetic component to a disease?