New Genetic Evidence Supporting the Theory there are Several Species of Killer Whales

The latest issue of the journal Genome Research, has an article where scientists report finding strong genetic evidence supporting the theory there are several species of killer whales (Orcinus orca).

Differences in behavior, feeding preferences and subtle physical features had the scientists postulating that there could be several species of killer whales. The scientists got the proof from using a relatively new method called, 'highly parallel sequencing' to map the entire genome of the cell's mitochondria from a worldwide sample of killer whales.

Two types of killer whales in the Antarctic that eat fish and seals, respectively, are suggested as separate species, along with mammal-eating "transient" killer whales in the North Pacific. Several other types of killer whales may also be separate species or subspecies, but for conclusive evidence additional analysis is required.

Using old technique the examination of mitochondrial DNA genome in one sample could have taken several months. But with the use of high throughput sequencing, researchers can complete the same analysis for 50 or more samples in just a few weeks.

According to the scientists understanding how many species of killer whales there are is critically to establish conservation priorities and to better understand the ecological role of killer whales in the world's oceans.