- Rob Stadler
“Junk DNA”: A concept that points to a “Junk evolutionary assumption”
According to our understanding of DNA function back in 2003, the Human Genome Project suggested that only a small fraction (1.2%) of human DNA had a function. The result was embraced by the evolution camp, because it fulfilled their predictions of “junk DNA”, vestigial leftovers from our evolutionary past. In the decade following the Human Genome Project, an international team of 400 scientists participated the follow-on ENCODE study, which vastly improved our appreciation of human DNA function. In a series of 30 papers published in 2012, the ENCODE study shocked the world by demonstrating that more than 80% of the human genome had known functions (compared to the original 1.2%). The >80% figure is likely to increase over time as we continue to learn.
One would think that this failed evolutionary prediction would lead the evolution camp on a short retreat to bury the now-embarrassing term “junk DNA” and to devise an explanation for how highly functional DNA fits within their theory. But those who bow at the temple of Darwin are loath to acquiesce. Ryan Gregory of the University of Guelph said, “I would like to think that most knowledgeable biologists who properly appreciate evolutionary theory and genomic diversity are well aware of the many problems with ENCODE’s claim.” Dan Gruar, an evolutionary biologist at the University of Houston, decided to take on the team of ENCODE scientists via the power of a mathematical model and the bold assumption that evolution via random mutations and natural selection is a fact (Genome Biol Evol, July 2017. DOI: https://doi.org/10.1093/gbe/evx121). Given that every new generation of humans acquires about 30 new mutations and that the large majority of mutations are detrimental (these facts are universally accepted), natural selection can only do so much to filter out the mutations and maintain healthy DNA. This filtering process requires a very large number of human births, coming from only the healthiest specimens, in order to propagate the healthier DNA. Otherwise our DNA would degrade over time. The higher the percentage of DNA that has a function, the more likely that a mutation in a random location will decrease fitness, thus requiring more filtering (i.e., requiring more reproduction from only the healthiest of humans). Graur estimated that if 100% of our DNA is functional, simply maintaining our current population and fitness would require every couple to produce a minimum of 24 children, wherein only 2 would go on to produce a next generation. In contrast, mutations that occur in non-functional portions of DNA are inconsequential, so there is less need for the filter of natural selection, thus reducing the required number of children per couple. If 80% of our DNA is functional (as ENCODE suggested), maintaining our current population would require every couple to have a minimum of 15 children. Given a realistic human reproduction rate of 3.6 children per couple, Gruar’s model estimated that no more than 25% of our genome can be functional. This is what the evolutionary paradigm predicts.
In contrast, the ENCODE study (backed by more than 400 scientists and a $400 million budget), demonstrated that at least 80% of our DNA is functional. The empiric evidence therefore stands opposed to the evolution model, but supports the “Genetic Entropy” model of John Sanford. Genetic Entropy says that our DNA is degrading slowly over time because of the slow accumulation of mutations – the opposite of evolution.
Which provides higher confidence: a result from a study conducted by 400 scientists, or a mathematical model from one scientist that starts with the assumption of evolution? Rather than discredit the ENCODE results, Graur’s model serves only to discredit his evolutionary assumption.