Komodo, the Magic Dragon

by Dr James Sleigh

To celebrate the appearance of PlayDNA on the BBC’s Dragons’ Den, we are diving into the mystical world of dragons…

Here be dragons

Powerful, fearsome, venomous. A rare breed of predator with sharp claws, razor-like teeth, and an insatiable appetite. No, we are not talking about Deborah Meaden, Peter Jones, or even Duncan Bannatyne of Dragons’ Den fame. We are describing the Komodo dragon, the largest living lizard, and native of the Indonesian Islands of Southeast Asia. But, do they deserve their dragon moniker?

They have no wings, and they can’t breathe fire, you say. Nor do they live for centuries, or like to hoard gold.

A real dragon
Photo courtesy of http://ngm.nationalgeographic.com

Not a real dragon
Photo courtesy of http://hollywoodlife.com

Nevertheless, these creatures, which can grow to over three metres in length and eat up to 80% of their body weight in a single feed, do possess an almost mythical ability worthy of the dragon name.

Miraculously, in separate zoos in the UK (Chester and London), two female Komodos, which were completely isolated from males, laid clutches of eggs that resulted in lots of baby dragons. This ability for females to produce offspring without mating with a male is known as parthenogenesis, and is very rarely seen in vertebrate species (those with a backbone like you and me). In fact, only about 1 in 1,000 vertebrates can reproduce in this manner. It was particularly unexpected that such a large animal as the Komodo dragon would join this rather selective group.

Intriguingly, all the virgin baby dragons were males. This is because of the interesting genetics of Komodos. Much like we have X and Y sex chromosomes (XX = female and XY = male), Komodo dragons have W and Z chromosomes. However, rather than females having two of the same sex chromosome like humans, female Komodos have one W and one Z chromosome while males are ZZ. When female dragons are isolated from males, through parthenogenesis they are able to duplicate either their W or Z chromosome (along with the rest of their non-sex chromosomes), resulting in eggs that are either WW or ZZ. The WW eggs do not survive, but the ZZ eggs produce viable male baby dragons.

Hello mummy!
Photo courtesy of BBC

It is believed that this ability to switch between sexual and asexual reproduction has evolved as a strategy to be able to survive in the Komodo’s natural habitat of isolated islands. Females finding themselves washed up on unpopulated islands are able to reproduce asexually, producing males for future mating.

Fascinating.

Not quite cloning, but I’m sure some of the BBC dragons would be interested in making similar duplicates of themselves so they could make twice as much money! What’s that? You want to know the outcome of PlayDNA’s adventure in the dragon’s lair? Well, you will just have to wait until Sunday to see how Dr. Sam and Dr. Stuart fared…

PlayDNA is on Dragons Den Sunday 2nd February BBC2 at 9pm.

How genetics is helping the snow leopard

Brrr! The snow is still falling here in Oxfordshire and has all but the bravest of us confined to our homes.

One animal that doesn’t mind the cold however is the majestic snow leopard.

Found throughout the major mountain ranges of Central Asia, including the remote Himalayas, the snow leopard (Panthera uncia) is among the most elusive of all the big cats.

Unlike us, snow leopards have a number of perfect adaptations for living in a cold mountainous environment. Their bodies are short and stocky, their fur is thick, and their ears are small and rounded, all of which helps to minimise heat loss. Their paws are wide, which distributes their weight better when walking on snow, and their tails are thick due to storage of fats and are very thickly covered with fur which allows them to be used like a blanket to protect their faces when they sleep.

Curiously the snow leopard cannot roar, and instead, much like a domestic moggy, they hiss, chuffle, mew, growl and wail.

Sadly, although perhaps unsurprisingly, the snow leopard is listed as an endangered species by the IUCN, the largest global conservation network. Just 3,000 to 7,500 individuals are believed to exist, although given its secretive nature it has been difficult for conservationists to work out exactly how many of these beautiful animals there are left in the wild.

Can you spot the elusive snow leopard? Yes, there really is one there! Tip: look just below the rocky outcrop on the left…
Image reproduced from: snowleopardblog.com/spot-the-snow-leopard, courtesy of Kim Murray, the Snow Leopard Trust’s Assistant Director of Science

This is where genetics has been invaluable in helping the conservationists estimate the numbers of wild snow leopard in certain areas.

Scientists in Nepal collected samples of “scat” (snow leopard poo to you and me) and, using the same genetic techniques we do in creating your PlayDNA portrait, profiled the ‘poo’ to work out how many individual snow leopards were in each area, and even what gender they are.

This is really important information to a conservationist as it allows them to see how human activity might be affecting snow leopard populations, identify areas of high conservation priority and assess the effectiveness of any potential conservation action. All with minimal interference to the snow leopard.

Let’s hope their efforts are rewarded by a resurgence in the numbers of these magnificent beasts.

– written by Dr Samantha Decombel, Founder (PlayDNA)

References:

http://www.biomedcentral.com/1756-0500/4/516

http://snowleopardblog.com