title: The Ecosystem Role of Viruses Affecting Eukaryotes
abstract: Viruses are an integral part of ecosystems, interacting and coevolving with their hosts in ways that include predations, niche cooperations and niche competitions. This chapter discusses the possible role of viruses in eukaryogenesis. It also mentions coregulation between virus and host, gene transfer from virus to host, and gene transfer from host to virus. Three historically significant discoveries of viruses affecting eukaryotes are mentioned, those are Tobacco mosaic virus in Crimea during 1