stressedadfff
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does anyone know
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why snps are more common in non coding regions than coding? (1 Viewer)
- Thread starter stressedadfff
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I believe you previously asked the same question on the below thread? 
stressedadfff
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omg thanks!!! i knew ive asked it before THANK YOU SO MUCH!!I believe you previously asked the same question on the below thread?
Yeah exactly what Hiva said.
If you want to go into even more detail, you can say that typically, coding portions of the gene are highly conserved. This is because a nucleotide change will likely have a more obvious effect on the protein due to an amino acid substitution, or some other change to the polypeptide chain. This means that mutations to coding portions are less tolerated, and are less likely to be passed on.
Mutations in introns tend to be less important because they are typically spliced out during RNA processing. Thus they are more tolerated as they tend to have a lower effect on the organism. Thus they are more likely to get passed on.
So ultimately, mutations in non-coding regions tend to have less of an overall effect on the organism, and hence why they are more tolerated. They are more likely to get passed on, and are therefore more common within a population.
An interesting metric (that is outside of the HSC scope but would be covered if you ever work in bioinformatics) is measuring the pLoF of a gene. pLoF means the probability of loss of function, which can tell you how tolerant a gene is to mutations. Different genes have different tolerances. For example, a gene that regulates critical function of cells may be very intolerant, whereas a gene that regulates some less important function may be more tolerant to mutations.
Also, different parts of the intron have different tolerances to mutations - for example the splice sites (donor and acceptor) are extremely intolerant to mutations and will always result in mis-splicing if disrupted. This is because you can think of them as the guide for splicing machinery to excise out introns and paste the exons together.
Finally, you can definitely have intronic mutations leading to disease. One that comes to mind is a hexanucleotide repeat expansion in a gene known as C9orf72. This typically leads to problems in neurons, which manifests itself clinically as ALS (the disease Stephen Hawkings suffered from).
If you want to go into even more detail, you can say that typically, coding portions of the gene are highly conserved. This is because a nucleotide change will likely have a more obvious effect on the protein due to an amino acid substitution, or some other change to the polypeptide chain. This means that mutations to coding portions are less tolerated, and are less likely to be passed on.
Mutations in introns tend to be less important because they are typically spliced out during RNA processing. Thus they are more tolerated as they tend to have a lower effect on the organism. Thus they are more likely to get passed on.
So ultimately, mutations in non-coding regions tend to have less of an overall effect on the organism, and hence why they are more tolerated. They are more likely to get passed on, and are therefore more common within a population.
An interesting metric (that is outside of the HSC scope but would be covered if you ever work in bioinformatics) is measuring the pLoF of a gene. pLoF means the probability of loss of function, which can tell you how tolerant a gene is to mutations. Different genes have different tolerances. For example, a gene that regulates critical function of cells may be very intolerant, whereas a gene that regulates some less important function may be more tolerant to mutations.
Also, different parts of the intron have different tolerances to mutations - for example the splice sites (donor and acceptor) are extremely intolerant to mutations and will always result in mis-splicing if disrupted. This is because you can think of them as the guide for splicing machinery to excise out introns and paste the exons together.
Finally, you can definitely have intronic mutations leading to disease. One that comes to mind is a hexanucleotide repeat expansion in a gene known as C9orf72. This typically leads to problems in neurons, which manifests itself clinically as ALS (the disease Stephen Hawkings suffered from).
specificagent1
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Would non coding dna making up the large majority of the dna also contribute to this? because only a small amount is actually coding dna
specificagent1
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oh ok makes sense. So they measure what the percentage of snps are in each section. But given that there are more non coding dna, doesnt it mean that there is a greater probability of snp occuring in the non coding dna. If i have 10 cookies but 7 are chocolate and 3 are mint, then i have more of a chance of breaking the chocolate cookies when i transfer them to their package? is there not more chances of snp occuring in non coding?