Project Description

In this study, we demonstrated the feasibility of generating genome assemblies from single adult nematodes using multiple displacement amplification. By testing the protocols on C. elegans, we were able to fully quantify the extent of bias and address it with existing analysis pipelines. With a genome size of 136.6-738.8 Mb in 13 nematodes, sequencing on a single MinION flowcell can be expected to provide approximately 37.8X depth of coverage. We demonstrate that a genome assembly and accurate gene annotations can be achieved with this workflow and further sequenced the genomes of 13 free-living nematodes. Of these genomes, four are the first reported in the Enoplia clade revealing their unusually large genome sizes and structures. Through phylogenomics, we established Enoplia as sister to the phylum Nematoda, suggesting a marine origin in the last common ancestor of nematodes. We overcame the stage of obtaining axenic culture whilst assembly and annotation can be achieved within two weeks of nematode isolation. Assuming that 1ug is required for long-read sequencing, combining MDA with ONT sequencing thus provides a cost- and labour- effective solution to generate complete assemblies in organisms with as little as 50 picograms of starting material.