ABSTRACT
The nuclear genome is the largest in the plant cell, both in terms of picograms of DNA and in the number of genes encoded. Nuclear DNA is packaged into chromosomes along with histones and non-histone proteins, all of which play an important role in gene expression. When the double helix of DNA was found, it was believed that many distinct molecules are present in a chromosome. Besides the conformations, DNA may form unusual structures that appear to be important in regulating gene expression. Denatured DNA will renature to reform the duplex structure if the denaturing conditions are removed. Renaturation requires reassociation of the DNA strands into a double helix, a process known as reannealing. In eukaryotes, most mRNAs undergo a fairly complicated series of modifications and processing events before translation occurs. These are chemical modifications to the two ends of the mRNA molecules, removal of introns, and RNA editing.
