Daily Times

Recently, a study has introduced the idea of dark DNA. Studying sand rats, researchers report finding gene activity (including RNA transcripts) apparently arising from undetected stretches of chromosomal DNA. This undetected region contained 88 genes found in other mammals, but not found in the chromosomal sequence data from the sand rat. Such “dark” areas of DNA appear to also be present in the chromosomes of chickens and gerbils.

Actually, the DNA is not missing or even completely undetected. Rather, current sequencing methods frequently fail to provide an accurate sequence for some DNA segments.7 Regions of dark DNA apparently are among these unsequenced sections. Using a different approach, researchers were able to derive sequence data for some of the dark DNA regions of the sand rat.

Several genes in this “dark DNA” appear to have a different sequence than their counterparts in other species. Among these differences, the dark DNA has a higher percentage of cytosine (C) and guanine (G). DNA regions with a high percentage of C and G are often more difficult to sequence, which helps explain why the sand rat sequences were not found in current chromosome sequence data banks.

One interpretation is that the dark DNA has undergone numerous mutations, which has caused its sequence to substantially differ from the analogous genes of other animals. These mutations resulted in an increase of C and G, making the sequences less detectable. By this interpretation, these areas of “dark DNA” may be mutational hotspots: regions where mutations occur at rates much higher than average.

From an evolutionary perspective, a high mutation rate has the potential to increase the pace of evolution. Since mutations can alter physical traits, more mutations may mean a greater variety of traits. The more variety of traits within a population, the more likely one (or more) of these traits will serve some benefit. This is standard Darwinism.

An evolutionary interpretation sees mutations not only as a source of unlimited physical changes, but as the engine for building new genetic systems and functions. In this framework, mutational changes drive universal common descent (i.e., all life shares a single, common ancestry). Therefore, universal common descent requires fish to evolve into amphibians and reptiles to transform into birds. Hotspots in the chromosomal DNA become a significant potential contributor to these dramatic transformations. Because of their high mutation potential, some evolutionists propose that areas of dark DNA could be “an underappreciated mechanism” driving the pace and direction of evolution.

In fact, a new article speculates that the mutation rate of dark DNA may be so great that natural selection cannot remove the deleterious mutations fast enough. This would seem to pose a problem, but the article actually suggests these deleterious mutations might be useful if the organism later faces a different environment. Presumably, what was deleterious then may become beneficial.

The future benefit of deleterious mutations is sheer speculation. Even placing such speculation aside, deleterious mutations are, by definition, harmful to the organism. Some may be more harmful than others. Yet, the more that deleterious mutations accumulate within members of a population, the more of a threat they become to the overall health of that population.