Whale dandruff reveals family ties

Bill Amos explains how DNA from whale dandruff holds the key to unlocking their family dynamics...
25 July 2014

Interview with 

Bill Amos, Cambridge University Department of Zoology


Bill Amos explains to Chris Smith how DNA from whale dandruff holds the key toRight Whale and calf unlocking their family dynamics...

Bill -  My career is rather serendipitous in that I did my PhD on the genetics of green fly, and it wasn't a very successful study!  I was wondering what to do next and I went to an inspirational talk by a guy called Alec Jeffreys, who was the guy who invented DNA fingerprinting - this way of identifying individuals and working out who's related to who, using genetic techniques, using DNA techniques.  I thought this was fantastic and I came back to Cambridge and I met this odd guy walking down the street with a bandana on his head.  I knew he was the weird guy in the department who disappeared for most of the year and he was a sailor and his whole research was on the behaviour of whales.  He asked me, he said, "Look, we've got some material.  We've got this study that we'd like to do some genetics on whales, but we don't know what to do."  I said, "Well, I've got the best technique you could think of."  Basically, I've never look back.  So, I started off two projects:  one on the grey seal up, in Scotland, and one on pilot whales, which are hunted in a traditional fishery in the Faroe Islands; and in both cases I was using DNA fingerprinting to work out who's related to who.

Chris -  And not who done it?

Bill -  Not who done it?  Well, slightly who done it as in who's the father on occasions, but yeah, we were trying to find out something about the ecology of these animals because of course, if you go to sea and look out at the sea, you see an awful lot of water without any whales in.  In fact, if there are any chemists out there, I once worked out that the sea has a concentration of whales of about 10-38 molar.  So, it's a very, very dilute solution of whales!

Chris -  So, two questions then - one, how do you find the whales, and, more importantly, how do you find out their genetic code?  What do you have to do?

Bill -  Well, first of all, you need to get some samples and in the Faroe Islands, they were hunting the whales.  I really hated being involved in this project, but it was an unusual circumstance and the whales, we're going to be dead anyway.  But normally, you don't have that as it were the luxury of access to those samples.  So, we were looking for other methods and at that time, there were people developing methods based on bows and arrows.  You go into the boat with a bow and arrow and on the end of the arrow would be a tiny little - like an apple corer - which was capable of taking little plug of skin with a rubber bung to stop it hurting the whale.  So, it just go bump and take a little plug of skin and you have it on a fishing line then you'd haul it back in.  We decided to go down a less invasive route, slightly more difficult, but a bit more glamourous.  So, we realised that whales actually shed skin like we have dandruff.  But of course, they have spectacular dandruff on occasions.

Chris -  Define spectacular.

Bill -  I've seen pieces of whale skin about a meter square like a little chiffon scarf sitting in the seawater.

Chris -  How would you recognise it?  What does it look like then?

Bill -  They're just little fragments of dark material and it depends what the whale has been doing.  If you're lucky enough to see a whale breech, that's when they leap out of the water and come down with a huge splash then you can actually smell the skin on the surface of the water, and if you dive into the water with a little aquarium net, if you get there before the fish, because of course, this is a bit of a source of food, you can scoop up bits.  Now, the nice thing is, that whales, you can identify them individually from the patterns of natural markings.  They accumulate scars and so, you take a photograph of the whale, you then follow it in the water, and as soon as it dives, the turbulence of the water around the tail when it dives means it sheds a bit of skin into the water and you then dive off your boat, and you hope to find some fragments that you can then link to that individual.

Chris -  And you can get the DNA out of those cells?

Bill -  Those bits of skin are big enough to get nice DNA out of.  And a student of mine working on humpback whales ended up with 650 individually identified animals and then you can start asking interesting questions because really, we don't understand much about the humpback whales' social organisation.  There are a lot of documentaries, but most of the science in terms of what they're actually doing and why, really remains to be found that...

Chris -  How do you actually use this because the whales are going to hang around in groups, aren't they?  They're social animals.  They like to be together.  So, how do you not know when you scoop up your whale skin with your nets that you're not scooping up a bit of me, a bit of you, a bit of this guy here?

Bill -  Fish are very good at hovering and keeping the water pretty clean.  So, you usually follow an individual and when it dives, you collect the skin from that.  Now, where we were working and I only got to go there once, but it was wonderful.  Two weeks of miraculous experience of swimming with humpback whales.

Chris -  It's all for the science.

Bill -  I've had quite a long career and I've spent 4 weeks actually swimming with whales.  In Hawaii, the whales are sensible.  When they want to reproduce, they swim to the nice warm waters around shallow, generally equatorial islands like Hawaii, like the West Indies, places like that, and the females give birth.  And then the female and her calf will stay together for a number of weeks suckling before they return up to the much richer waters up in the arctic in the northern hemisphere and the Antarctic in the southern hemisphere where they really feed up during the summer on huge sholes of either crustaceans or fish, depending on the species.  So, we can follow the mother and her calf, those are together.  Sometimes they have an escorting male, we still don't know why the male hangs around with the female, whether he's waiting for mating opportunity or whether he's simply maybe the father of the previous year.  In fact, we disproved that genetically.  He certainly isn't the father of the previous year.  But on the other hand, other males will sit there singing.  You've heard of the song of the whale and it's amazing.  You can actually hear this song above the water.  So, you're on a boat and you hear this amazing (makes a whale sound) incredible sound coming...

Chris -  He deserves a round of applause for that.  [clapping]

Bill -  These guys sit there 30 foot down, making this incredible sound and each male has a different song.  And we really don't know why.  Occasionally, another male will come along and perhaps challenge that male and then sit in the same place singing his song.  But nobody to my knowledge has ever seen a female visit the male and mates with the male.  Maybe they're just amusing themselves.  We don't know.

Chris -  So will the ultimate aim then, you're going to follow these guys and then do these genetic testing to see if that male ever does end up a father of next year's calf and it's just that you end up with a sort of escort, escorting someone else's baby, but with the aim to mate the next year?

Bill -  Absolutely.  Well, we're interested in any kinds of relationships there.  The other group that seems much more oriented to mating is called the rowdy groups, which is a bunch of males who all seem to be fighting for position near to a female who we kind of assume is fertile and is able to conceive at this point.  They're really violently -you  may have seen documentaries of them slamming into each other.  Again, we really don't know who's the winner, whether any of them are the winner.  Maybe the female just finally gets rid of them and goes and chooses the male she actually wants as a partner.  So, these are big questions and you can answer them genetically.

Chris -  Any questions for Bill?

Kasian -  My name is Kasian and my question is, you said that when whales swim, their skin comes off.  Well, how does their skin come off?

Bill -  Well, it's just like people.  The skin is the layer that separates you from the environment.  And the environment is harsh.  It's got sunlight coming down.  You might get sunburn.  There is a theory that even whales get sunburned - believe it or not - if they stay at the surface too long.  So, one of the defences that all animals have is to keep shedding the outer layer and keep replacing it from underneath.  So, if you cut your finger, you don't have a cut for life.  Soon, the skin grows over and mends that cut.  So, it's constantly replaced.  When does it come off?  Well, it comes off a little bit all the time but if you suddenly move and you're a whale in the water, then you shed a bit more than you would do normally, and that's when you find the bigger pieces.

Chris -  Georgia...

Georgia -  What happens to all the barnacles and things that live on the whales when they shed their skin?

Bill -  Some whales, not all of them, but some species have barnacles which live on them for varying lengths of time.  You may notice the right whale - ironically, it's called the right whale because it was the right whale to hunt, and it's the right whale to hunt because it's the only whale that floats when it's dead.  And if you just harpooned a 50-ton animal that sinks and you're in a small boat, you haven't done yourself a lot of favours.  So, the Right whales have these crusts on the front of their faces which are white and crusty and those are barnacles, and they stay on for life as far as we know.  They clearly have evolved mechanisms for staying there very thoroughly.  Mostly, animals that try to sit on the whale and use it for something to grow on are shed pretty rapidly.  Whale skin is very dynamic and they're capable of losing any unwanted passengers.

Emily -  I'm Emily and what if you get hit with the fluke of a whale.

Ginny -  Can you just tell us quickly what a fluke is?

Bill -  The fluke is the name you call the tail of the whale.  The fluke of the whale, particularly the big whales is a huge weapon.  They use it against each other.  They use it for signalling.  If they hit a diver with it, that diver would not be a diver anymore unfortunately, he'd go into the marine ecosystem.  So, they're very powerful.  I don't know if you've seen a film of it, but one way killer whales hunt fish is they school them into a big ball where the fish don't know what's happening and they're milling around in what looks like a glitter bowl of fish swimming around.  One of the whales will come in and smack the ball hard with the tail and it's so powerful, you'll see the water is suddenly full of all these stunned fish.  So, it doesn't have to swim after them and just hoover them up where they are, so it's very powerful.

Bob -  Hi.  My name is Bob.  Can you say roughly how much genetic variation there is between members of the same species of whale or between whale species and how much there is in common between human DNA and whale DNA?

Bill -  There's a lot of variation in whales and there's a lot of variation between the species of whales, such that you can use genetics to identify not only different species of whale, but also, which ocean they came from.  I've been asked to do some work in the past when they got suspicious shipments of some kind of meat and they wanted to know whether it was an illegal species of whale and I did some genetics and I was able to tell them that the particular shipment was in fact minky whale meat which the smallest of the baleen whales with the big throat pleats.  It poorly came from the Pacific Ocean.  That made sense - it was a box from the Far East.  In fact, the reason they were suspicious, the customs officer said, "Well, it did have whale meat in large letters on the outside."  So, I guess that raised their suspicions.  In terms of the difference between humans and whales, there is plenty.  Clearly, we're very different to look at, but we know that we are 99% similar to chimpanzees.  So, if you get a stretch of a thousand of your DNA letters, then only 10 of them on average will differ between us and chimpanzees.  Between whales, it's probably more like 2 or 3%.  But it's not massive.  The genes are entirely recognisable. Actually, mammals aren't that old in terms of the divergence of the DNA.  What matters is how the genes have changed very subtly.  Don't forget that if you get one mutation, you might have a really nasty disease or one mutation might make your eyes blue as opposed to brown.  Small changes can make a big difference in genes.

Scott -  I'm Scott, I belong to Emily.  My question is actually for the entire panel.  I'm sure there's tons of young aspiring marine biologists out there.  What would be the one bit of advice you would share with them, I guess early on?

Bill -  Passion gets you a long way.  If you're really bright, that's great because some of the academic stuff is tough but there are niches in which most people can work: some people are really good at organising and chatting to people and they can do fundraising for conservation;  some people are really good at writing, they can go into science journalism.  So just be passionate about it. Ironically, at school, the one subject I really hated was genetics and I actually chose my degree course to avoid doing genetics.  But actually, when I started doing the degree, I did some genetics and I thought, "Wow!  This is cool."  You suddenly see something, you get the inspiration, take hold of it.

Chris -  Mark Spalding, what would you say?

Mark -  I second the passion thing.  I think if you've got the passion, it will take you a long way.  I'd also really say if you can get experience wherever you are, even just getting out and volunteering with people with organisations, going along the university and say, "Can I help?" this kind of thing, it sets you out of the crowd because it is quite a competitive field to find work, but enjoy it and get experience.

Chris -  Viola.

Viola -  Yes, that's basically what I was going to say, get out there.  Get experience, do some volunteering.  Go along to things like a bird ringing demonstration for example if you just want to see what these things are like.  I think field work is really important to energise your passion if you have it and help it grow.

Chris -  Lloyd...

Lloyd -  I'd say, don't be afraid of asking questions.  If there's something you're interested in then ask questions about it, find out about it, and don't be afraid of chasing a dream, just follow that dream down...


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