Cloning as a technology has been around for a long time now. The first animal, Dolly the sheep, was successfully cloned in 1996. The first horse was cloned in 2003 and since then the equine industry has found a use for cloning. Top geldings have been cloned so that they can pass their genes on via a stallion clone.
Diversity is Key
One of the biggest arguments against cloning is that you are reducing the diversity of the species. We need diversity as when a species is all closely related, they are likely to all have the same weaknesses. For example, there are currently roughly 540 Siberian Tigers left in the wild. If a new disease evolves which is potentially deadly to the tigers, the more genetic diversity, the more are likely to survive. Whereas if they are all closely related, they are all likely to share the weakness and could quickly become wiped out.
Endangered Animals Have Less Diversity
Unfortunately, as humans we have put a lot of animals at risk of being extinct. We often react too late to the signs and then have very small numbers left to save the species. The only survival for these animals includes a level of inbreeding or close breed, where the genetic variation is much lower than ideal. While this can be great for increasing numbers, they are still at risk due to their lack of diversity.
But this isn’t just wild animals. The same can be said for some rare breeds of horse. The Suffolk Punch is at risk with just 300 left in the UK. These numbers are so low that we are now at risk of drastically reducing their genetic diversity. In fact many of our heavy horse and native breeds are at risk.
Over the years we have really improved our reproductive technology. Not only can we artificially inseminate horses, we can make female animals produce extra eggs and put them into surrogate animals so that a female can have more offspring at a time. We are also able to sex semen to around 99% success rate, meaning we can choose the gender of the offspring. All these things are currently used in selective breeding programmes around the world.
All these technologies allow us to increase the number of animals in a breed or species. Using super ovulation, we can take lots of eggs from a rare Suffolk Punch mare and inseminate mares of other breeds with them. If we are lacking females in the population, we can sex the semen to make sure we are inseminating with female semen, guaranteeing a female offspring. We can also clone valuable breeding animals, allowing them to double the amount of offspring possible.
But as previously touched on, once the numbers get so low, it is the lack of variation what causes the problem, not the low numbers.
Frozen Samples Adding Diversity
Luckily people recognised some of the issues facing some breeds and species and took samples of sperm, eggs and stem cells and froze them. At the time, there wasn’t the technology or money to do much with these samples. But now they could be a much needed lifeline.
Recently an endangered Przewalski horse was cloned from a frozen stem cell from the 80s. This colt has very different genetics to the current wild population and will be a very valuable stallion in the years to come for adding some diversity back to the population.
We could apply this to all at risk species and breeds. Even if we don’t have older samples, we should be collecting as many samples as we can now. These can be used down the line to help inject diversity when it is needed.
In David Attenborough’s newest documentary A Life On Our Planet, he really drives home the importance of global biodiversity. Not only will this allow more species to thrive, but it could also be key to reducing global warming. This idea of cloning genetically diverse animals could be a good way of restoring some diversity to at risk species.
I found this idea of cloning for diversity really interesting as it has always been viewed as a way to reduce genetic diversity. But now it seems it really could be an effective way of adding old genetics back into current populations.
Last Updated on 08/10/2020