The hybridisation capture of population-level mitochondrial genomes from
environmental DNA
Abstract
Population genetic data is often essential to inform conservation
management. Understanding the distribution of genetic variants within
and between populations can reveal novel insights into genetic
connectivity and evolutionary processes. However, obtaining such data
using invasive approaches such as tissue sampling may negatively affect
the very species we are seeking to protect. Thus, interest in using
non-invasive environmental DNA (eDNA) techniques for identifying genetic
variation within target species populations has grown. Along with this
interest comes the desire to expand the amount of population genetic
information that can be obtained from eDNA to increasingly large
fragments of the genome, such as entire mitogenomes. Here, we introduce
an eDNA hybridisation capture approach to sequencing complete
mitochondrial genomes of New Zealand fur seals (Arctocephalus forsteri)
(Māori: kekeno) from marine water samples. We show that our approach can
recover up to 99% of the fur seal mitogenome. Furthermore, we present a
pipeline to extract haplotype diversity from such eDNA population
genetic data. Haplotypic variation identified using this approach
matches previously identified patterns of intraspecific genetic
variation from fur seal tissue samples, suggesting that eDNA methods can
accurately identify mitochondrial variation. Our study demonstrates that
whole mitogenomes can be recovered using hybridisation capture
enrichment of eDNA and indicates that eDNA may be a promising tool for
population genetics. Within this context, we discuss some of the key
challenges that must be overcome before the promise of eDNA can be fully
realized.