What is preventing medical researchers from fixing DNA abnormality?
Answers:
The lack of technology is what is preventing researchers from finding and fixing DNA abnormalities.
In our bodies, we have ~20,000 -25,000 genes surrounded by each cell. And these genes (as well as the DNA sequences between these genes) are composed of 6 Billion base pairs (or. A, T, G, C).
DNA base disease can because be many things such as, loss of a gene (resulting in 19,999 -24,999 genes), a internal deletion or rearrangement of a gene ( which would not cause a unknown gene to be created therefore you'd have 20,000 -25,000), or a single base couple mutation (changing an A to a G ... for example ... resulting in a total of 20,000 -25,000 genes, or a different base pair composition resulting contained by a change from 6,000,000,000 base pairs to 5,999,999,999 base pairs within common with the "normal sequecne').
In auxiliary to problems with genes themselves... genetic disease can be cause by mutations in regions outside of genes (the intervening sequences between genes call "Promotors" and the "3' Untranslated Region". These two regions are critical in determining when and where genes are expressed (they provide "instructions" for allowing gene expression ... this allows a heart cell to work like a "heart cell" and a "quill cell" to grow hair ... although both cells have ALL genes, merely a subset are 'actively functioning' ...). So, it is also possible that the "instruction" regions can also be mutated resulting in an absence of gene expression.
(For example, Fragile X mental retardation ... is caused by a specific type of 'promoter' mutation/abnormality that prevents expression of the gene ... the gene, itself, is completely intact ... however it is never expressed because the "Instructional" region are diluted and non-functional)
Sooo ... when you think about the huge numbers of genes, and all of the intervening regions (instructional regions up to that time and after genes) and potential ways for causing a DNA abnormalities. You can kinda begin to appreciate how truely difficult it is to if truth be told (inexpensively) identify a mutant gene in a geneticially sick person. Maybe in 10 years from in a minute, everyone it will be easier/inexpensive for each person (sick and healthy) to know their genetic composition... and be able to receive an accurate diagnosis of genetic disease.
Ok... so, lets fast forward 10 years from now ... we will adjectives have our DNA sequences. And, the little boy, born with fragile X syndrome will have the diagnosis. The doctors know that , although he have a normal copy of the fragile X mental Retardations gene (FMR1... that's the actual gene name), the instructional region is damaged, and his brain cells do not produce the acutual gene product (FMRP ... Fragile X mental retardation protein). In proclaim for the little boy to live a normal life... the doctors know that they have to introduce a functional copy of the gene (with the promotor region) or replace the worn out promoter with a working one. The problem is ... how do they actually get a "good" copy of DNA into the right genome-spot and into EVERY SINGLE brain cell ... and THAT is exactly where on earth we stand now. Surely the technology is there to identify many (But not all) genetic diseases, but we can't fix them because in attendance isn't an effective way to get the "healthy" genes subsidise into each other cells.
Of course, researchers are actively trying to figure out how to receive the genes into cells (read about gene therapy http://en.wikipedia.org/wiki/Gene_therap… )
.... soooo, fixing genetic disease is not a trivial process ... but this is a "hot topic" surrounded by the science research world, and people are working really hard to figuring this stuff out.
hope this explanation is accepting and not too complicated ... lemme know if anything is unclear
(Other body cells do not express FMR1, it is a brain-only protien... so even though skin cells may enjoy an abnormal Fmr1 gene/promoter ... it has no adverse effect, cuz skin cells don't want FMRP) Source(s): My research and studies.
To change a genetic abnormality, you would need to change the DNA contained by every single cell in your body.
The kind of technology to do such a thing is far from individual developed. Very far.
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