Tuesday, 14 June 2016

DNA can say so much...

Commentary by Sara Tavares

The amazing work done for more than 20 years in British Columbia, photographing and identifying (all) killer whales, gave us unprecedented knowledge about this species. The detailed photographic dataset created in British Columbia is invaluable for the conservation and monitoring of the local populations.

But sometimes photographic identification is not enough and other kinds of information from the individuals becomes important, such as its specific genetic "fingerprint" - DNA.

This blog post by Dr. Carla Crossman, molecular and marine biologist with the Vancouver Aquarium Marine Science Centre’s Coastal Ocean Research Institute, is a great example of how invaluable genetics studies are when working with wild populations. Last April, 2 dead individuals washed out in British Columbia in a state of decomposition that did not permit identification based on appearance. But using existent knowledge of the genetic variation across populations, the Vancouver Aquarium Marine Science Centre’s Coastal Ocean Research Institute discovered to which population the individuals belonged to by their genetic code. Working long hours to get this information as soon as possible, the molecular biologists in the Institutes’ Conservation Genetics Lab were able to tell that both whales belonged to the fish-eating resident population and more specifically to the southern community! Amazing, right? This was possible due to previous studies by Dr. Lance Barrett-Lennard, currently senior marine mammal scientist at the Vancouver Aquarium Marine Science Centre’s Coastal Ocean Research Institute, that discovered which variations in the genetic code distinguished the killer whale populations.

3 males traveling together. Are they from the same family and therefore genetically related? Uncovering this is one of the goals of the Icelandic Orca project.

We are currently working on building up this kind of genetic knowledge on the Icelandic killer whale population to help us monitor the status of the population. One of the goals of our project is to map the genetic relatedness among individuals and understand the genetic variability within the population. It will be some years until we uncovered all this but during the last 2 years we made great progress collecting small biopsy samples of skin from photo-identified individuals. Lately, we have been trying to find the best genetic markers to use on this population (because the variations in the genetic code are not the same among populations) so that we can start uncovering this vital information about the animals.

But, as Carla Crossman so well shows on her blog post, genetic analysis can be a slow process... Even just extracting DNA from a small piece of skin from a single individual whales takes several days! And extracting DNA is just the very first step! Then you need to test different genetic markers, optimise protocols and only once all that is complete can you start going through all the small skin biopsies to start gathering information from different individuals. So it can usually be many months until this type of analysis is complete. We will keep you posted about new developments on the very exciting genetic studies being conducted!