Which enzyme hydrolyzes DNA during isolation, potentially degrading the DNA sample?

Considering the Dumbo mutation in Problem 37, what kinds of additional evidence would help you determine whether Dumbo is a mutation of a regulatory sequence or of a protein-coding gene?

Thinking back to the discussion of gain-of-function and loss-of-function mutations, explain why gain-of-function mutations are often dominant and why loss-of-function mutations are often recessive. Give an example of a type of gain-of-function mutation that is dominant and of a loss-of-function mutation that is recessive.