synonymous vs conservative missense mutation

[hiro]

i don't know the differences between these 2 mutation... look the same to me...
and how do we know which mutation will be synonymous/ missense by looking at the change of codon?

[Katy_Bobbles]

Hi hiro.

Synonymous (or silent) mutation is when there is substitution of 1 base for another. However this type causes no change in the resultant protein because the codon encodes the same amino acid

e.g. If CAU is changed to CAC it does not matter as both encode histidine.

Missense (or non-synonymous) mutations cause base substitution resulting in a codon which encodes a different amino acid

e.g. Sickle cell disease is caused by a GAG (which encodes glutamate) to GTG mutation resulting in the formation of valine instead. As a result Haemoglobin S is formed instead of the normal haemoglobin A/A2

Hope that makes sense

[kotoreru]

Good explanation, I like it

[Darby]

Recent data suggest that silents may not be silent - codon changes, even from one to another that "on paper" produce the same amino acid, still change things like methylation sites and may have distinct effects on the expression rates of the alleles.

Isn't it fun when "basic knowledge" just won't sit still?

[hiro]

icic...more clear now thx~~

[MrMistery]

also note codon bias, which seems to be much more important that we originally thought

[ramya]

hi hiro!
synonymous mutations are those that donot change the amino acid even if there is a substitution of one base in the place of other(degeneracy of genetic code) and it doesnt make any change in the protein structure or funtion or watever u say.but non-synonymous mutations change the aminoacid even with a single substitution of a base.jus like in sickle cell anaemia.
To know how far that non-synonymous mutation is harmful we have to check the percentage of conserveness of that particular sequence where v found that mutation.This would probably help the researchers to understand the affect of that particular mutation in the gene expression....
hope i didnot confuse u