Amitav Ghosh's novel The Calcutta Chromosome is a science-fiction which deals with subalter voice. In this paper I have discussed that how Ghosh has written an alternative hisory for the suabltern and how he establishes a connection between subaltern and the science-fictional term, the posthuman. I also argue that through such representation Ghosh proposes a open ended way to think about the subaltern future as well.