| Molecular evolution has become an important area of science in past few decades. It helped in unraveling information stored in gene sequences, which represent an invaluable compilation of the history of life on Earth. Gene duplication is one of the fundamental features of molecular evolution. Duplicate genes that are stably preserved in genomes have divergent functions. The general rules governing the functional divergence, however, are not well understood and are controversial. According to Ohno (1970), after duplication one daughter gene retains the ancestral function while the other gains novel functions. The question we tried to answer here that how do newly duplicated genes survive and acquire novel functions, and what role does gene duplication play in the evolution of genomes and organisms. An evolutionary model using lattice model genes is developed which explores the effect of neutral and positive selective pressures on the duplicates in acquiring a new adaptive function through the process of neofunctionalization. Modeling under such conditions suggests that subfunctionalization plays as a transition state to neofunctionalization rather than as a terminal fate of duplicated genes. |