"While discovery of the cause itself is noteworthy, the method by which it was determined could have a profound effect on how wildlife mortality events are investigated in the future. Described in a study published today, April 16, in the journal Nature Communications, the researchers call this new approach "forensic genomics." It involves a combination of field surveys, toxin testing and genomic scans.
In the case of red abalone, the finding was the result of fortunate timing.
"Just months before the mortality event, we had sequenced the entire genome of several red abalone in the same area," said co-author Laura Rogers-Bennett, a senior environmental scientist with the California Department of Fish and Wildlife working at the UC Davis Bodega Marine Laboratory. "What we had, in essence, was a baseline, so we went back to the same site after the mortalities and did a whole genome scan of the survivors."
With both sets of data in hand, they compared the two groups using a computer program and found a set of clues that pointed them in a very specific direction.
"Parts of the genome were significantly different than what you'd expect by chance," said Rogers-Bennett, an affiliated faculty member of the Karen C. Drayer Wildlife Health Center at UC Davis.
When they investigated those outliers, they found that their function was to aid in detoxification. The results supported their hypothesis that a harmful algal bloom producing a Yessotoxin was the major cause of the mass mortality rather than exposure to other potential toxins".