The existence of large amounts of non-coding DNA (up to 97% in humans) in the genomes of eukaryotes has been used as an argument against intelligent design (and the role of a Creator) and as an argument for the random process of evolution. However, a recent study13 has shown that eukaryotic non-coding DNA (also called "secondary DNA") is functional as a structural element in the nucleus. Previously, there were two evolutionary theories that attempted to describe the reason for the existence of non-coding DNA One theory stated that non-coding DNA was "junk" that consisted of randomly-produced sequences that had lost their coding ability or partially duplicated genes that were non-functional. The second theory stated that non-coding DNA was "selfish", in that it consisted of DNA that preferentially replicated more efficiently that coding DNA, even though it provided no selective advantage (in fact was somewhat detrimental in that it was parasitic).
The new study examined the genomes of the single-celled photosynthetic organisms know as Crytomonads. These organisms exist as vastly different cell sizes, with the nucleus being proportional in size to that of the cell. Researchers discovered that the amount of non-coding DNA was proportional to the size of the nucleus, suggesting that more non-coding DNA was required in larger nuclei. As an added proof, the nucleomorph, a small piece of DNA contained within the plastid that codes for itself and photosynthetic function, was not changed in size, despite changes in cell size and nuclear content.
The new study is a stunning rebuttal to the evolutionary theories that attempt to discredit design and promote concepts such as "junk" DNA and "selfish" DNA.
According to the authors:
"Furthermore, the present lack of significant amounts of nucleomorph secondary DNA confirms that selection can readily eliminate functionless nuclear DNA, refuting 'selfish' and 'junk' theories of secondary DNA"
Beaton, M.J. and T. Cavalier-Smith. 1999. Eukaryotic non-coding DNA is functional: evidence from the differential scaling of cryptomonal genomes. Proc. R. Soc. Lond. B. 266:2053-2059.
http://www.evidence.info/design/designgonebad.html#junk
The new study examined the genomes of the single-celled photosynthetic organisms know as Crytomonads. These organisms exist as vastly different cell sizes, with the nucleus being proportional in size to that of the cell. Researchers discovered that the amount of non-coding DNA was proportional to the size of the nucleus, suggesting that more non-coding DNA was required in larger nuclei. As an added proof, the nucleomorph, a small piece of DNA contained within the plastid that codes for itself and photosynthetic function, was not changed in size, despite changes in cell size and nuclear content.
The new study is a stunning rebuttal to the evolutionary theories that attempt to discredit design and promote concepts such as "junk" DNA and "selfish" DNA.
According to the authors:
"Furthermore, the present lack of significant amounts of nucleomorph secondary DNA confirms that selection can readily eliminate functionless nuclear DNA, refuting 'selfish' and 'junk' theories of secondary DNA"
Beaton, M.J. and T. Cavalier-Smith. 1999. Eukaryotic non-coding DNA is functional: evidence from the differential scaling of cryptomonal genomes. Proc. R. Soc. Lond. B. 266:2053-2059.
http://www.evidence.info/design/designgonebad.html#junk
