Genetic degradation drives scientists to develop more accurate gene editing technology

Genetic degradation drives scientists to develop more accurate gene editing technology

https://www.wired.com/story/whats-next-for-crispr/

DNA consists mainly of four different bases: guanine (G), cytosine (C), adenine (A), and thymine (T). G makes a pair only with C and A forms a pair with T.

Genome's GC content is inclined to change to AT content. This is due to the special feature of the cytosine base: A methyl group (CH3), referred to as an epigenetic marker, may be attached to cytosine. The cell uses these markers for several tasks, the most important of which are gene suppression / activation, the secretion of the gene from transcription, and the modification of expression of the gene, i.e. the expression thereof, according to the adaptation of the organism. Also in cell differentiation, or identity, these markers play an important role. Without the epigenetic markers, the cell is a so-called a pluripotent stem cell that is ready to specialize in any task, as long as it is only programmed.

DNA may be exposed, for example, to oxidative stress as a result of dietary factors, environmental toxicants or poor lifestyle. Oxidative stress typically causes a reaction called deamination in DNA causing sequence changes. If the unmethylated cytosine deaminates, it becomes a different type of base, uracil. DNA repair mechanisms detect this error and correct the change at last in cell replication (base excision repair). But if the cytosine is methylated, it changes in deamination to thymine and this change is not corrected by DNA repair mechanisms. For genomic grammar to be correct, the original  pair of the cytosine is also replaced by changing guanine to adenine. This is how a genetic GC> AT mutation occurs.

 

Scientists are now developing accurate genomic editing methods that can restore the AT base pairs back to GC pairs. Approximately half of the 32,000 pathogenic point mutations in the human genome are due to the change in preference of the above GC pairs to AT pairs.

Excerpt: "Other scientists at Harvard and the Broad Institute have been working on an even more daring tweak to the Crispr system: editing individual base pairs, one at a time. To do so, they had to design a brand-new enzyme—one not found in nature—that could chemically convert an A-T nucleotide pairing to a G-C one. It’s a small change with potentially huge implications. David Liu, the Harvard chemist whose lab did the work, estimates that about half of the 32,000 known pathogenic point mutations in humans could be fixed by that single swap."

GC content turning to AT content is a phenomenon happening in all organisms and it causes rapid progressive genetic degradation. The specialty is eg. the fact that when bacteria start to have abundant AT content in its genome, they become harmful or pathogenic bacteria. A mammal, on the other hand, will typically be carnivorous when the GC content starts to run low.

Scientists' rush to develop these editing methods tells us that evolution is not happening. Mutations cause problems for the genome, such as information loss and diseases. Evolution theory is the most serious heresy of our time. Do not get lost, good people.