‘Junk DNA’

Those of you who have been following this blog, as well as Evolution News & Views, for some time, will be aware that I have previously discussed, across multiple articles, the phenomenon of endogenous retroviral inserts into the genomes of primates. Those familiar with the debate over origins will also be familiar with the various arguments for common descent which are based upon these fascinating genetic elements. A friend recently asked me if I would compile my thoughts on the topic into a single article, and hence that is what I intend to do here. Since my previous articles on the topic (and since my progression from undergraduate to postgraduate status), my knowledge of the subject has increased and I Read More ›

Philosopher Michael L. Peterson explains junk DNA for us at BioLogos in “Evolution and the Deep Resonances between Science and Theology, Part 5” (July 20, 2011):

Evolution is the only rational way to account for the molecular uniformity of all organisms, given that numerous alternative structures and fundamental processes are, in principle, equally likely. Moreover, the accumulation of damaged or “junk” DNA (mutations that do not affect function and thus are not subject to negative selection), passed on over time to species further down that branch of the Tree, makes the probability that evolution did not occur infinitesimally small.

Okay, so that means that if much that is thought junk turns out not to be, “the probability that evolution did occur infinitesimally small.” Right? Read More ›

For many of us, an important characteristic of science is self-correction. We are proud of the way new findings catalyse re-evaluation and, if corrections are needed, the development of new knowledge. If you are like this, be prepared to be shocked when you read Jonathan Wells’ latest book. The concept of Junk DNA was widely held by evolutionary biologists during the 1990s, but only a few were prepared to expose the hypothesis to tests of its validity. Yet this is when publications started to accumulate that reported functionality in genetic material widely regarded as “nonsense”. Instead of alerting popularisers of science to be cautious, these writers treated the new data as unrepresentative exceptions. They pressed on with their claim that Read More ›

He certainly drew the desired Darwinian conclusion:

“The amount of DNA in organisms,” Dawkins wrote in 1976, “is more than is strictly necessary for building them: A large fraction of the DNA is never translated into protein. From the point of view of the individual organism this seems paradoxical. If the ‘purpose’ of DNA is to supervise the building of bodies, it is surprising to find a large quantity of DNA which does no such thing. Biologists are racking their brains trying to think what useful task this apparently surplus DNA is doing. But from the point of view of the selfish genes themselves, there is no paradox. Read More ›

In 2009, University of Chicago geneticist Jerry A. Coyne compared predictions based on intelligent design with those based on Darwinian evolution. “If organisms were built from scratch by a designer,” he argued, they would not have imperfections.

“Perfect design would truly be the sign of a skilled and intelligent designer. Imperfect design is the mark of evolution; inf fact, it’s precisely what we expect from evolution.” According to Coyne, “when a trait is no longer used or becomes reduced, the genes that make it don’t instantly disappear from the genome: Evolution strops their action by inactivating them, not snipping them out of the DNA. From this we can make a prediction. We expect to find, in the genomes of many species, silenced, or ‘dead,’ genes: genes that once were useful but re no longer intact or expressed. In other words, there should be vestigial genes.”  Read More ›

In 2010, University of California Distinguished Professor of Ecology & Evolutionary Biology John C. Avise published a book titled Inside the Human Genome: A Case for Non-Intelligent Design, in which he wrote that “noncoding repetitive sequences–‘ junk DNA’–comprise the vast bulk (at least 50%, and probably much more) of the human genome.” Avise argued that pseudogenes, in particular, are evidence against intelligent design. For example, “pseudogenes hardly seem like genomic features that would be designed by a wise engineer. Most of them lie scattered along the chromosomes like useless molecular cadavers.” To be sure, “several instances are known or suspected in which a pseudogene formerly assumed to be genomic ‘ junk’ was later deemed to have a functional role in Read More ›