Penelope-like retrotransposons in the genome of the Asian blood fluke Schistosoma japonicum (Trematoda: Schistosomatidae)

Abstract

Mobile genetic elements (in particular, retrotransposons) make up a significant part of eukaryotic genomes and are one of the main sources of genomic variability and instability. More than 60 years have passed already since their discovery, but, nevertheless, certain classes of them, such as Penelope-like elements (PLEs), remain poorly studied. In this work, we present the results of in silico search for PLEs in the genome assembly of the Asian schistosome S. japonicum (one of the most epidemiologically important human parasites). We present a new evaluation of their representation in the S. japonicum genome and showed that their high heterogeneity apparently reflect several transposition events. It was demonstrated that PLEs in the schistosome genome are represented by two groups of canonical copies differing by amino-acid sequences of RT and EN domains. Data on the representation, structural peculiarities, possible functional load, and evolution of Penelope-like retroelements of the parasite are discussed.