forensic DNA test
concept of allele-specific oligonucleotides
(ASOs) can be extended to
The DNA sequences of the
Cytochrome Oxidase I gene
for many species of scallops, including two found in the Northwest
Atlantic, Sea Scallops (Placopecten
magellanicus) and Icelandic Scallops (Chlamys icelandica). The
test shown here combines an anchor
primer for a DNA sequence
both species (ScallopR2)
position 932 with primers specific for either species (PmaCOIF1
are differentiated at positions 313 and 473, respectively. The PCR amplification product
from Placopecten is
thus expected to be
932 - 313 = 619bp in length,
shorter 932 - 473 = 459bp in Chlamys. That is, the size of the
fragment indicates species identity directly.
KA Johnstone, & SM Carr (2007) Forensic Sci Int'l,
"The Case of
the Scurrilous Scallops", a fisherman had a load of
scallops that he claimed were from the open fishery for Islandic
Enforcement officers suspected they were instead from the closed
fishery for Sea scallops (Placopecten).
proportion of bycatch from the closed fishery might be
considered acceptable, the legal question was: What fraction of
total catch was from the prohibited species? DNA was extracted from
scallops and amplified in the multiplex SSO test with the three primers. Of
the 80 scallops in the test above, all but eight (blue arrows)
the larger DNA fragment,
which indicates that 90% are Placopecten.
complete series of more than 900 scallops from two vessels,
almost two-thirds were Placopecten.
in conviction and fine.
The multiplex SSO
rapid, direct means of forensic identification of large
population sample series, without the necessity of secondary DNA sequencing, RFLP mapping, or
and can be adapted to other loci and species.