Transmissible spongiform encephalopathies(TSEs) or prion diseases are a closely related group of diseases, whose exact etiology is unknown, but is generally accepted to be related to protease-resistant prion protein PrP. PrPc is normally present in cells and its disease counterpart PrPsc is postulated to occur due to a rare stochastic change. The selfish gene hypothesis is a generally well accepted concept in evolutionary biology. Genes can be likened to the board of a company and proteins can be likened to share-holders. Here it is being hypothesized that a rogue share-holder protein's 'selfish' replicatory tendency might be the explanation for TSEs. The present hypothesis predicts existence of other examples of rogue share-holder protein and also predicts that examples would be found in lower life-forms as well.