Junk DNA, or noncoding DNA, may actually have important functions in gene regulation, repair, and evolution. It explains differences in genome size and can contain ultraconserved information. Some sections were once active genes and may play a role in disease inheritance.
Junk DNA is DNA that appears to have no discernible function. However, the term ‘junk’ is a bit misleading, as research into junk DNA has suggested that it may actually play an important role in the evolutionary history and life of many organisms. Rather than junk, this DNA may in fact be stored for a critical reason, and researchers have begun exploring junk DNA with the goal of learning more.
Some people refer to junk DNA as “noncoding DNA,” referring to the fact that it does not encode proteins that express themselves in the phenotype of the host organism. Whatever you call it, the percentage of junk DNA in the genome is often quite high. In humans, for example, 95% of the genome is made up of non-coding DNA. Junk DNA appears to explain much of the differences in genome size between different organisms, as some plants and animals have large amounts of junk DNA, while others have less.
All kinds of information can be contained in junk DNA. For example, huge sections of non-coding DNA are what’s known as “ultraconserved,” meaning they’ve remained the same for millions of years. Scientists know that these sections are ultra-conserved because they are identical in numerous organisms, sometimes in the case of only distantly related creatures. When you hear statements like “animal X and the human genomes are 98% identical,” it is because of ultra-conserved DNA.
By looking at differences in junk DNA between organisms, the researchers were able to learn more about when these organisms diverged from their common ancestors. The fact that non-coding DNA has been preserved for millions of years would seem to indicate that it has some sort of function, perhaps in the role of gene regulation, gene repair or gene evolution. Non-coding DNA also appears to act as a buffer in the genetic code which may play a role in DNA replication.
There is some evidence that some of the sections in the junk DNA were once active genes, leading researchers to refer to these sections as “pseudogenes.” At one point in evolutionary history, these genes were either dismissed as unimportant or replaced by other genes, but they have remained quietly in the background. Non-coding DNA may also play a role in the inheritance of diseases and other traits, meaning it might not be junk after all.
Protect your devices with Threat Protection by NordVPN
