Analysis of Simple and Imperfect Microsatellites in Ebolavirus Species and Other Genomes of Filoviridae Family

Abstract

Background: Microsatellites have evoked the interest of researchers owing to their applications in different fields such as DNA fingerprinting, genetic mapping, population genetics, forensics, paternity studies and evolution. Objectives: The present study focused on the analysis of simple sequence repeats (SSRs) in genomes of seven species from three genera of the Filoviridae family. Materials and Methods: Genome sequences of seven species from the Filoviridae family were assessed by the National Center for Biotechnology Information (NCBI), microsatellites were extracted using the IMEx software, and statistical analysis was performed Microsoft Office Excel 2007. Results: A total of 516 microsatellites and 14 Compound Simple Sequence Repeats (cSSR) (also known as compound microsatellites) were extracted. Evidently, the conversion of SSRs to cSSR was low. Mononucleotide A/T was the most prevalent followed by dinucleotide AC/CA and trinucleotide AAC/CAA. Highest incidence of SSRs (mon-/di-nucleotide motif) was observed in RNA Dependent RNA Polymerase (RDRP) gene whereas tri-nucleotide motif was maximally localized in nucleoproteins (NP). Conclusions: The salient features of simple and compound microsatellites in Filoviridae family have been highlighted herein. Microsatellite regions with higher mutation rates compared to the rest of the genome play a crucial role in genome evolution by acting as a source of quantitative genetic variation. The SSR mutation rate is known to be affected by motif length, motif sequence, and number of repeats and purity of repetition. The functional role of tandem repeats in viruses, remains to be fully elucidated. However, with the repetitive sequence allegedly acting as a hot spot for recombination, we postulate their involvement in genetic events such as recombination, replication, and repair mechanisms that drive sequence diversity leading to the formation of the genetic basis of adaptation.