Abstract:
Narwhals (Monodon monoceros) are elusive animals, and have inspired myths, legends,
and awe for centuries, which is exacerbated by their inaccessibility in the heavily iced
high Canadian Arctic waters. With a current “Near Threatened” classification by the
International Union for Conservation of Nature and Natural Resources (IUCN) and a total
population estimate of roughly 80,000 animals, unlocking the genetic code of this species
may be the key to beginning to unravel much of the mystery that surrounds them, both in
the past and the future. This study compared a drilling method and a grinding method to
provide a reliable, minimally destructive method to extract ancient narwhal DNA from
samples that need to remain physically undamaged for display purposes. Short pieces of
unprocessed pre-1972 narwhal tusk (n = 50) were obtained from Pond Inlet, Nunavet
Canada. This study utilized narwhal cytochrome b mitochondrial DNA (mtDNA) data
from the National Center for Biotechnology Information’s (NCBI) GenBank, where two
primers, NAR-4 (581 bp) and NAR-6 (241 bp), were created for use in Polymerase Chain
Reaction (PCR). Using a grinding technique on the tusk surface, the study outlines a
reliable method to extract ancient deoxyribonucleic acid (DNA) from narwhal tusk and
amplify it for further analysis using PCR. The amplified DNA from the grinding method
was compared to the traditional drilling method using electrophoresis and the grinding
method yields the same level of amplification of DNA as the drilling method. The
extracted DNA was then sequenced using the designed primers and compared to narwhal
mitochondrial DNA samples in GenBank to positively confirm narwhal as the sample’s
identity. This study’s grinding technique caused a significant reduction in physical
marring to the surface of the narwhal tusk samples and provided evidence for a reliable
method to extract ancient narwhal DNA while preserving historical samples for
undamaged display.
