Use it or lose it? Researchers investigate the dispensability of
our DNA| October 2, 2008 Our genome contains many genes encoding
proteins that are similar to those of other organisms,
suggesting evolutionary relationships; however, protein-coding
genes account for only a small fraction the genome, and there
are many other DNA sequences that are conserved across species.
What are these sequences doing, and do we really need them at
all? In a study published online today in Genome Research
(www.genome.org), researchers have delved into this mystery and
found that evolution has actively kept them in our genome.
Before the human genome was sequenced, researchers estimated the
genome might contain upwards of 140,000 protein-coding genes,
but surprisingly, sequencing revealed only about 20,000,
accounting for less than 2% of the entire genome. Previously,
Dr. Gill Bejerano of Stanford University found that lurking
within the other 98% of the genome are stretches of sequences,
known as ultraconserved elements, whic