Hello Supriya,

Since you have achieved 49 marks in the gate examinations for the life science, you have a slight chance to get admission in the IIT's,

The admission eligibility requirements may be relaxed to 5.5 on a 10 point scale

and for further details, you can even visit our website, where there is a detailed description of all the major courses offered by the IIT's and which one would be the best for you.

https://www.careers360.com/articles/Universities/Various-PhD-programmes-IIT