Earl Grey: a fully automated user-friendly transposable element annotation and analysis pipeline

Abstract

Transposable elements (TEs) are major components of eukaryotic genomes and are implicated in a range of evolutionary processes. Yet, TE annotation and characterisation remains challenging, particularly for non-specialists, since existing pipelines are typically complicated to install, run, and extract data from. Current methods of automated TE annotation are also subject to issues that reduce overall quality, particularly: (i) fragmented and overlapping TE annotations, leading to erroneous estimates of TE count and coverage; (ii) repeat models represented by short sections of total TE length, with poor capture of 5 and 3 ends. To address these issues, we present Earl Grey, a fully automated TE annotation pipeline designed for user-friendly curation and annotation of TEs in eukaryotic genome assemblies. Using nine simulated genomes and an annotation of Drosophila melanogaster, we show that Earl Grey outperforms current widely-used TE annotation methodologies in ameliorating the issues mentioned above, whilst scoring highly in benchmarking for TE annotation and classification, and being robust across genomic contexts. Earl Grey provides a comprehensive and fully automated TE annotation toolkit that provides researchers with paper-ready summary figures and outputs in standard formats compatible with other bioinformatics tools. Earl Grey has a modular format, with great scope for the inclusion of additional modules focussed on further quality control and tailored analyses in future releases.