Forum:Why do different nucleotides have different substitution rates?

Question

[tangoo21]

Why do different nucleotides have different substitution rates?

[tangoo21]

Do mutations occur evenly in the whole genome? How about their maintenance?

[mikhail.shugay]

Partially because polymerase to tends prefer transitions over transversions when it is making errors during library prep PCR stage (ref) :)

Answer 1

[dariober]

Different nucleotides have different chemical properties so their mutation rates differ. C tends to mutate to T relatively easily for example.

(Sorry, can't quote any reference just now and I'm not a chemist so don;t take me too seriously...)

[Michael]

See here: Ti/Tv Ratio Confirms Snp Discovery. Is This A General Rule?, this is called transition/transversion ratio.