José M. Martín-Durán, Bruno C. Vellutini, Ferdinand Marlétaz, Viviana Cetrangolo, Nevena Cvetesic, Daniel Thiel, Simon Henriet, Xavier Grau-Bové, Allan M. Carrillo-Baltodano, Wenjia Gu, Alexandra Kerbl, Yamile Marquez, Nicolas Bekkouche, Daniel Chourrout, Jose Luis Gómez-Skarmeta, Manuel Irimia, Boris Lenhard, Katrine Worsaae, Andreas Hejnol

bioRxiv 2020.05.07.078311; doi:10.1101/2020.05.07.078311

Conservative route to genome compaction in a miniature annelid

Genome assembly (PacBio, 73.8 Mb, 95.8% BUSCO genes, 2.24 Mb N50, 4.87% transposable elements, 14,203 protein-coding genes) for the annelid Dimorphilus gyrociliatus, a meiobenthic segmented worm. Synteny with the scallop genome is visible. The Hox cluster is present and lacks only one gene, post1. However, in situ hybridisation suggests lack of temporal colinearity. The Myc pathway “lacks the regulators mad (in D. gyrociliatus) and mnt (in all Dinophilidae), a condition also shared with the appendicularian O. dioica”. “Open chromatin regions [ATAC-seq peaks] are short and mostly found in promoters.” “Promoters [CAGE] are narrow (<150 bp) and use pyrimidine-purine dinucleotides as preferred initiators.”