The human genome contains less than
   2% coding exons within genes.
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   The remaining DNA consist of:
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<BR><LI> introns and regulatory sequences such as enhancers
<BR><LI> unique  noncoding  DNA  contains many pseudogenes (genes that have
accumulated mutations and became nonfunctional)
<BR><LI> repetitive DNA are sequences that are repeated many times; much of
these are
	  + transposable  elements  that  can "jump" between chromosomes,
leading to transpositions.