Plant biologist William Thompson and his colleagues at the North Carolina
State University (NCSU) has described the process that corn uses to unravel
and replicate small segments of its chromosomes at different times in the
August issue of The Plant Cell.
Thompson said that DNA replication has been well characterized in animal
cells, but little is known about the replication timing programs in plant
cells. A single nucleus from a single cell of a corn plant typically
contains two sets of chromosomes, each containing over 2 billion base pairs
of DNA and over 30,000 genes. As DNA cannot be replicated in a compact
state, higher organisms have evolved sophisticated programs, called
replication timing programs, to unravel and replicate small segments of
their chromosomes at different times. The researchers found that the
replication program in corn differs in several important ways from those of
animals and yeast.