(May 4, 2018 at 5:09 am)CDF47 Wrote: From Wikipedia:
In genomics and related disciplines, noncoding DNA sequences are components of an organism's DNA that do not encode protein sequences. Some noncoding DNA is transcribed into functional non-coding RNAmolecules (e.g. transfer RNA, ribosomal RNA, and regulatory RNAs). Other functions of noncoding DNA include the transcriptional and translational regulation of protein-coding sequences, scaffold attachment regions, origins of DNA replication, centromeres and telomeres.
The amount of noncoding DNA varies greatly among species. Often, only a small percentage of the genome is responsible for coding proteins, but a rising percentage is being shown to have regulatory functions. When there is much non-coding DNA, a large proportion appears to have no biological function, as predicted in the 1960s. Since that time, this non-functional portion has controversially been called "junk DNA".[1]
The international Encyclopedia of DNA Elements (ENCODE) project uncovered, by direct biochemical approaches, that at least 80% of human genomic DNA has biochemical activity.[2] Though this was not necessarily unexpected due to previous decades of research discovering many functional noncoding regions,[3][4] some scientists criticized the conclusion for conflating biochemical activity with biological function.[5][6][7][8][9]Estimates for the biologically functional fraction of our genome based on comparative genomics range between 8 and 15%.[10][11][12] However, others have argued against relying solely on estimates from comparative genomics due to its limited scope. Non-coding DNA has been found to be involved in epigenetic activity and complex networks of genetic interactions, and is being explored in evolutionary developmental biology.[4][11][13][14]
So? Do you even understand what you pasted?
After all, it also says:
"some scientists criticized the conclusion for conflating biochemical activity with biological function."
The neutral gene theory explains why the evolutionary process benefits from junk DNA. Basically, parts of the DNA get duplicated as a form of mutation. If this doesn't lower the fitness of the agent then it stays. Although it does not have an effect, it effectively opens up part of the evolutionary search space for further mutations to occur in future generations. I deliberately use this in my evolutionary runs. I add in a duplication rate of 1% so the genotype can grow more complex over the course of the evolutionary run. This leads to the equivalent of junk DNA and I strip away parts of the phenotype that it generates to make processing more efficient.
This isn't just a hypothesis. This works in practice. It's useful. If the theory wasn't correct I wouldn't be able to use it.