RasiRNA

Classification

There are at least three Argonaute (Ago) subfamilies that have been found in eukaryotes. Unlike the Ago subfamily which is present in animals, plants, and fission yeast, the Piwi subfamily has only been found in animals. RasiRNA has been observed in Drosophila and some unicellular eukaryotes but its presence in mammals has not been determined, unlike piRNA which has been observed in many species of invertebrates and vertebrates including mammals; however, since proteins which associate with rasiRNA are found in both vertebrates and invertebrates, it is possible that active rasiRNA exist and have yet to be observed in other animals. RasiRNAs have been observed in Schizosaccharomyces pombe, a species of yeast, as well in some plants, neither of which have been observed to contain the Piwi subfamily of Argonaute proteins. It has been observed that both rasiRNA and piRNA are maternally linked, but more specifically it is the Piwi protein subfamily that is maternally linked and therefore leads to the observation that rasiRNA and piRNA are maternally linked.