The age of museomics : How to get genomic information from museum specimens of Lepidoptera

Sammanfattning: In the age of museomics, the ability to sequence the genetic material from old museum specimens provides an invaluable and often untapped molecular resource. The application of the latest Next-Generation sequencing (NGS) technologies to such specimens allows us to utilise the diverse biobank that is natural history museums. These approaches provide the opportunity to study both extinct or difficult to collect taxa. The aim of this thesis is to apply NGS techniques to museum specimens of Lepidoptera, to better investigate the types of data generated and their uses.In the first chapter, we use a targeted enrichment (TE) approach to sequence nuclear loci from museum specimens dating back to 1892 for 35 taxa across the order Lepidoptera. Loci recovery ranged from 500-1,747. The success of this technique across the specimens highlights the usefulness of such a kit to study the entire order, thereby enabling the potential to resolve both shallow and deeper nodes in the phylogeny.In the second chapter, we applied the TE approach to three moth families belonging to the superfamily Geometroidea. Thirty-three museum specimens collected between 2001 and 1892 were sequenced from the families Epicopeiidae, Sematuridae and Pseudobistonidae. We recovered up to 1,383 raw loci per individual. Loci recovered in 20 or more specimens were carried forward for phylogenetic analysis, with a final data set consisting of 378 loci. These loci from another 19 publically available genomes and transcriptomes were combined to complete our dataset. We find strong support for the hypothesis that Sematuridae is the sister group to Epicopeiidae + Pseudobistonidae.Further expanding on our results from the TE approach, in the third chapter we apply whole genome sequencing (WGS) to expand our dataset. We sequenced whole genomes of 30 museum specimens of Epicopeiidae and Sematuridae. Recovery of the 387 loci from the TE experiment ranged from 20 - 94%. The resulting phylogeny confirms the phylogenetic relationships within these families. Additionally, we compared the data generated between the two approaches, presenting the advantages and disadvantages of each approach.In the final chapter, we investigated the usefulness of museum specimen WGS for population genomics studies. Data was generated for 13 specimens of Pieris napi, a common butterfly in Sweden. The availability of a recently published genome allows us to demonstrate that ~81% of the recovered DNA is from the target specimen. Average genomic coverage was 15.6X for nuclear DNA, and 1,963X for the mitochondria. We found that individuals originating from Abisko are genetically distinct from the remaining P. napi populations. This study highlights the potential of museum specimens for looking at changes in population genetic dynamics through time.In summary, we show the usefulness of various museomics applications. In particular, we focus on the use of TE and WGS for phylogenomic studies. Additionally, we highlight that WGS sequencing can also be utilized for population genetic-based studies, opening a window to the past.