Historical collections of tropical marine mammals are an excellent
resource for ancient DNA
Abstract
The ability to predict ancient DNA sequencing success in natural history
collections is critical to reducing the amount of destructive sampling
of a finite resource. So far, studies investigating such success have
predominantly focused on taxa with ranges restricted to temperate or
cold environments at northern latitudes which likely aids DNA
preservation. Here, we report remarkably high aDNA sequencing success in
Sirenia, herbivorous marine mammals of which the distribution is
currently constrained to the global tropics. We investigate 91 samples
from 85 specimens comprising all four contemporary species and one
extinct species, comparing different sample types (cranial/post-cranial
bone, skin and cartilage), species, collections, and material age. We
obtained remarkably high (e.g. > 20%) endogenous DNA
preservation for the majority (e.g. ~57% percent) of
samples. Sequencing success was linked to sample type, with cranial
bones (including petrous and tympanic bones) yielding significantly
higher endogenous DNA. Additionally, we obtained variable, but
potentially superior DNA results for preserved cartilage and hide
samples that can be associated with historical bone. Although such
tissue is not always present, this type of material is easy to sample,
with very limited destructive impacts on the associated bones and we
therefore highlight its untapped potential as a source of DNA. Overall,
our results show the high success of ancient DNA retrieval from
historical collections of species with a tropical distribution expanding
on the types of specimens that are available for temporal genomic
analyses.