Only 3% of human genomes are protein-coding DNA and scientist believes that the rest of the 97% are so-called ‘junk’ DNA which contains no genetic information. Recent research has found that tandem repeats, which are short stretches of DNA that are repeated, exactly influence the activity of the neighbouring genes.
Tandem repeats, a common example of ‘junk’ DNA, determine how tightly DNA is wrapped around a protein called nucleosomes which affects the level of activity of the gene. Also, scientist found out that these repeats are pretty unstable. They change their number of repeats frequently as DNAs are copied and these changes allow them to shift the gene’s activity effectively according to the changing environment, a key of survival to evolution.
Scientists test their theory by conducting a test using yeast cells, with one test-tube that has gene with tandem repeats and the other with the repeats removed. The results show that the test-tube with the repeats, scientists are able to identify the cells that have a great increased in gene activity and the test-tube without the repeat was unable to undergo fast evolution.
Hence, these ‘junk’ DNAs ability to adapt to changes very quickly gives organism an advantage in surviving countless evolution. Without them, cells would die as they would not be able to adapt to changes quickly enough. So, these ‘junk’ DNAs are exactly important life saviours in every organism.
Reference: VIB (the Flanders Institute for Biotechnology) (2009, May 30). Saved By Junk DNA: Vital Role In The Evolution Of Human Genome. ScienceDaily. Retrieved May 31, 2009, from http://www.sciencedaily.com /releases/2009/05/090528203730.htm
Posted by: RuBin Chua (41830143), Monday P2
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