1. Answer TRUE or FALSE.  If the statement is TRUE, explain or give a supporting example.  If the statement is FALSE, either correct the statement or give a counterexample.

   1. The yeast two-hybrid system works because the DNA-binding and activation domains have to be on the same protein.

2. The leucine zipper domain is not a DNA-binding domain.

3. The placement of activation sites at the lac operon and at eukaryotic genes is similar.

4. Many transcription factors in eukaryotes and prokaryotes are known to be modular with multiple functions.

5. Combinatorial transcription control does not occur in prokaryotes.

6. The mutations at the trp operon that affect anti-termination are most likely seen as acting as recessives.

7. A contig is a random collection of clones used for mapping DNA.

8. The most frequent type of mutation in humans is an autosomal dominant mutation because of the inherent redundancy (quadruplication) of the human genome.

2. Explain how to identify potential enhancer elements in Drosophila.

Answers