HELEN PILCHER
Evolution is speeding up. The world hasn’t seen change on this scale since the demise of the dinosaurs. And it’s all our fault. Meet the mutants and clones determined to survive.
Science writer Helen takes a look at our impact on evolution. “Now humans can deliberately amend the DNA of living things. We can rewrite the code of life, but this is only the beginning,” she says.
Warning! You may find the following facts shocking! On a ranch in Utah, there are goats that contain spider DNA. They don’t have eight legs and they can’t spin webs, but the unusual bleaters do have a superpower of sorts. They make spider proteins in their milk. The proteins can be spun into silk and the material is so strong that scientists think one day it could be used to make suspension cables.
Meanwhile, in Argentina, wealthy polo players are cloning their best ponies. Now copies of elite equines compete in high-profile competitions, whilst in South Korea, cloned sniffer dogs patrol the arrivals lounge at Seoul Incheon Airport.
Flabbergasted? Then let me drop one more bombshell. I was able to use the Internet to source and buy a genetically modified wolf pup. All grown up, he now lives in our house where I let him sleep on our bed and play with our children. Is it madness? Let me explain…
Altering course
For most of the last three billion years or so, life on Earth was shaped by natural forces – such as the changing of the seasons, the shifting of tectonic plates, and the waxing and waning of giant ice sheets. Evolution tended to happen slowly, with species crafted across millennia. Then, a few hundred thousand years ago, along came bolshie, big-brained primates that decided to call themselves Homo sapiens. As we spawned technology and dribbled around the globe, things started to change.
Forty thousand years ago, we began to domesticate wildlife, starting with the wolf. Along the way, we inadvertently changed the DNA of these lifeforms and rerouted their evolutionary trajectory. The beast that slumbers at the foot of my bed is the product of this. His DNA differs from that of his wild ancestors by around
0.5 per cent, so you could say that he’s been genetically modified. He is, of course, a dog.
After wolves, we domesticated other animals. A few hundred years ago, we started to pair key individuals together in a process called selective breeding. This generated the many domestic varieties that surround us today, from Holstein cattle to Merino sheep. About 20 years ago, we developed the ability to clone mammals and this, too, has become a tool of selective breeding. Now, in the last 10 years, a new suite of molecular methods enables scientists to deliberately alter the DNA of living things with pinpoint precision. Animals such as the spider-goat are the outcome.
Evolution is the ability of life to change over time. It’s underpinned by spontaneously occurring changes to the genetic code, but now humans can deliberately amend the DNA of living things. We can rewrite the code of life, but this is only the beginning.
Humans are now altering the planet on an unprecedented scale. Natural habitats are being razed, cities are expanding, poaching is taking its toll, and invasive species are being transported around the globe. The world is now almost 1°C warmer than it was before widespread industrialisation, and
“We see nothing of these slow changes in progress, until the hand of time has marked the long lapse of ages.” Charles Darwin
the temperature continues to increase.
For those species that fail to adapt, it is the end of the road. Scientists estimate that dozens of species go extinct every day, and that extinction rates are a thousand times greater than during pre-human times. These losses are our doing. Meanwhile, the survivors are racing to keep up with the pace of environmental change. Human activity is causing evolution to speed up, fuelling the emergence of novel characteristics, new species and bizarre hybrids.
Meeting in the middle
In the far north, as the sea-ice melts, polar bears are moving southwards, whilst grizzly bears are expanding their range to the north. Somewhere in the middle, the two species are meeting and mating. The result is a hybrid with characteristics of both parent species.
Pizzly bears, as they are called, have the slender neck of a polar bear but the humped shoulders of a grizzly. They have intermediate-coloured fur and feet that, in appearance, fit somewhere in-between the flat paddles of the Arctic species and the clumpy stompers of its North American relative.
No one knows how common or otherwise this oddity is, but we do know that pizzlies are breeding and bringing up young. In 2010, when a pizzly bear was shot in the Canadian Arctic, genetic tests revealed that the animal was, in fact, a second-generation individual with a grizzly father and a pizzly mother – a grizzly pizzly bear.
From the mules engineered by ancient Greeks to the cattle-bison crosses or ‘beefalo’ produced in North America today, humans have a long history of creating hybrids. It’s another way that our species influences evolution, and the pizzly bear is just one example.