4.  Which of the following would represent a mutation?

a.  a change in the base sequence of DNA              b.  crossing over in meiosis
c.  both (a) and (b)                                                          d.  neither (a) nor (b)

The information in DNA is located in the ORDER (SEQUENCE) of the bases.  If this order changes, the information changes.  By definition, a change in the genetic information is a mutation. Although crossing over enhances diversity of gametes, crossing over does not introduce NEW genetic material.

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Emma Erdahl, Associate Professor of Biology
Northern Virginia Community College
Revised 8/23/00