Retroviruses, Their Domesticated Relatives and Other Retroinvaders: Potential Genetic and Epigenetic Mediators of Phenotypic Variation

Abstract T his chapter is a very brief introduction to exogenous and endogenous retroviruses and other genomic mobile elements whose mobility is conditioned by transient passage through an RNA stage. This passage is mediated by transcription of the element with

host cell RNA polymerase, followed by reverse transcription of the resulting RNA and integration of the eDNA copy into a new position within the genome. Due to this reverse transcription stage, all of such mobile elements are termed retroelements {REs}. The chapter is not a comprehensive review, but rather a textbook-style narrative aimed at making the reading of the following chapters easier.