One “good” thing about the sluggish economy is all the discounts restaurants are offering. My favorite: two meals for the price of one!
It’s in this spirit that I offer two recent scientific discoveries this week for the price of one article. And what a deal for skeptics of the evolutionary paradigm! Both discoveries undermine one of the best arguments for biological evolution: junk DNA.
According to evolutionary biologists, junk DNA results when undirected biochemical processes and random chemical and physical events transform a functional DNA segment into a useless, molecular artifact. This “junk” piece of DNA remains part of an organism’s genome solely because of its attachment to functional DNA. In this way, the junk DNA persists from generation to generation.
Evolutionists also highlight the fact that in many instances identical (or nearly identical) segments of junk DNA appear in a wide range of related organisms. Often, the identical junk DNA segments reside in corresponding locations in these genomes. For evolutionists, this clearly indicates that the organisms shared a common ancestor. Accordingly, the junk DNA segment arose prior to the time that the organisms diverged from their shared evolutionary ancestor. Evolutionists ask, “Why would a Creator purposely introduce nonfunctional, junk DNA at the exact location in the genomes of different, but seemingly related, organisms?”
Recent studies on junk DNA provide a response to this question—junk DNA actually possesses function. (For a detailed discussion of discoveries that indicate the functional utility of junk DNA, see either Who Was Adam? or The Cell’s Design.)
Transposons, a class of junk DNA, have received a lot of attention recently. Also known as transposable elements (TE), transposons are mobile pieces of DNA with highly repetitive sequences. TEs duplicate themselves and then insert randomly into the genome, presumably creating junk DNA along the way. It turns out that TEs play a critical role in regulating gene expression. For example, recent research shows that in the plants Arabidopsis thaliana and Arabidopsis lyrata, TEs, chemically modified with methyl groups, reduce the expression of nearby genes.1
In another study, researchers from Great Britain and France demonstrated the opposite effect. They have observed that TEs in the genome of the bacterium Neisseria meningitides contain promoters that drive the expression of genes adjacent to the TEs.2
Studies like these continue the trend of the last several years: researchers are uncovering more and more examples of the functional importance of junk DNA. In light of this on-going advance, it is becoming harder and harder to maintain that genomes are riddled with the vestiges of the evolutionary process. Instead, it is becoming increasingly apparent that genomes are elegant, sophisticated systems, worthy of a Creator.
- Jesse D. Hollister et al., “Transposable Elements and Small RNAs Contribute to Gene Expression Divergence between Arabidopsis thaliana and Arabidopsis lyrata,” Proceedings of the National Academy of Sciences, USA 108, no. 6 (February 8, 2011): 2322–27.
- Azeem Siddique, Nicolas Buisine, and Ronald Chalmers, “The Transposon-Like Correia Elements Encode Numerous Strong Promoters and Provide a Potential New Mechanism for Phase Variation in the Meningococcus,” PLoS Genetics 7, no. 1 (2011): e1001277.