[rjohnp]

So I saw in reference to some performance data on the IonTarget Seq Exome, the poster presented and ASHG, by LT. So they had a metric on the poster Ts:Tv, I did not at first get it, but now I believe it to be just a measure of perfomance, i.e. that you captured appropriate fractions of the exome and the predicted ration of Ts:Tv is present.

Is that correct in thinking that it is just a q.c. score to see how your seq exp. performed.

Ts/Tv refers to the ratio between transitions and transversions, the two classes of nucleotide chemical changes. Shown below (shamelessly nicked from http://en.wikipedia.org/wiki/Transition_%28genetics%29)



Changes where the base remains e.g. a purine A>G transition are more liley to occur through various chemical changes, than a change from purine to pyrimidine (A>T). Thus, Ts/Tv tends to be ca. 4, though this does vary in targetted experiments such as whole-exome.

Random sequencing errors would (presumably, depending on the cause) cause both classes equally, and so ts/tv would trend towards 1.

Basically, yes, it's a QC thing.