switching site

[swĭchĭng]
n.
  1. Any of the break points in a DNA sequence at which a gene segment unites with another gene segment and causes genetic rearrangement of the sequence, as in the production of the immunoglobulins.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.