Question: Ti Tv ratio and their usefulness in exome sequencing
gravatar for mangfu100
20 months ago by
Korea, Republic Of
mangfu100440 wrote:

Hi all.

I am a beginner in the bioinformatics and I have some questions.

When I read some papers regarding the mutational landscape, nearly all of them described the Ti Tv ratio in terms of mutation spectrum with some pretty figures. Therefore I would like to apply this statistics to my research but I couldn't find its definition in a easy way and how to calculate it. Also, I have read some articles that nowadays ti/tv ratio has little impact when it comes to analyzing exome sequencing.

Therefore, I would like to ask you the following questions:

1) Ti Tv ratio: how to calculate it? Is there a website or tools that get them in an automatic way? If not, what should I know before writing some codes by myself?

2) for exome sequencing, all the things are equally applied when analyzing whole genome sequencing data?

sequencing next-gen genome • 3.3k views
ADD COMMENTlink modified 20 months ago by Evgeniia Golovina640 • written 20 months ago by mangfu100440
gravatar for Evgeniia Golovina
20 months ago by
Evgeniia Golovina640 wrote:


The Ti/Tv ratio is simply the ratio of the number of transitions to the number of transversions for a pair of sequences. There is a worked example of this calculation on the snpSift homepage that may clarify this point.

1) VariantEval and SnpSift can be used to calculate the transition transversion (Ti/Tv) ratios.

2) Yep. According to literature survey, the Ti/Tv ratio should be approximately 2.1 for whole genome sequencing and 2.8 for whole exome sequencing. If you have a mix of non-exonic and exonic data and you don't have a whole genome then you can get Ti/Tv somewhere between 2.1 and 2.8.

ADD COMMENTlink modified 20 months ago • written 20 months ago by Evgeniia Golovina640

Just to add to the answer above that Ti/Tv ratio of 2:1 for whole genome sequencing generally represents spontaneous and neutral mutation. 

ADD REPLYlink modified 20 months ago • written 20 months ago by Ashutosh Pandey10k
Please log in to add an answer.


Use of this site constitutes acceptance of our User Agreement and Privacy Policy.
Powered by Biostar version 2.3.0
Traffic: 518 users visited in the last hour