Gene duplication plays an impoant role in the evolution of aEUR'

mRNA (most likely) Gene duplications are impoant forces of genome evolution which change genome size and lead to the evolution of new gene functions. Gene duplication (or chromosomal duplication or gene amplification) is any duplication of a region of DNA that contains a gene; it may occur as an error inhomologous recombination, a retrotransposition event, or duplication of an entire chromosome. The second copy of the gene is often free from selective pressure-- that is, mutations of it have no deleterious effects to its host organism. Thus it accumulates mutations faster than a functional single-copy gene, over generations of organisms. This freedom from consequences allows for the mutation of novel genes that could potentially increase the fitness of the organism or code for a new function. The two genes that exist after a gene duplication event are called paralogs and usually code for proteins with a similar function and/or structure. By contrast, ohologous genes are ones which code for proteins with similar functions but exist in different species