There has been a lot of talk about cloning lately.

This technology has tremendous potential in the world of science; however, there are questions that have been raised about its use in agriculture. That’s not to say that this technology cannot benefit agriculture, but the reasons it is being marketed to bucking bull producers has not been fully explained. I’ve heard the speeches by the cloning companies and I have to admit, they give pretty convincing reasons to clone your animals. I’ve heard skeptics say that, after they heard the pitch, even they thought about loading up a bunch of animals to have them cloned. So this isn’t a matter of misunderstanding or misinterpreting the technology. On the contrary, you realize that there’s a great potential for its use. Unfortunately, if something sounds too good to be true, it probably is.

The process of cloning is actually a pretty straightforward procedure from a technical perspective. You take the DNA from one animal, implant it into an embryo and you put it in a recipient female for the embryo to turn into a calf with the same genotype as the DNA donor. The success rate is not very high in cloning, but those marketing the technology tell you that it’s worth it when you get animals of the same genetic makeup of your top animals. There’s also a pretty high economic cost to cloning animals. This is justified, the salesmen claim, because you’re working with proven genetics instead of having to spend the time and money trying to create that “perfect animal” you already have.

But here’s what they’re not telling you: You don’t get the same animal you got from the DNA donor animal. Yes, the genotype is the same but the animal is not. How can this be if the genotype determines the constitution of the animal? Well, there are a few pretty big factors that influence this. First, there is DNA methylation that is responsible for turning on different genes as I will explain. Secondly, there are other environmental factors that contribute to temperament and behavior. Temperament = genotype + environment. I will also cover this momentarily.

Let’s start off with DNA methylation. Forgive me for the advanced genetics, but this is probably the single most important reason why scientists do not think cloning is a 100% guarantee. DNA methylation is a form of chemical modification of DNA. This can be inherited without changing the DNA sequence. This is important when you consider that you can compare cloned animals with the donor animals and the gene sequence is identical. What you can’t see during this comparison is the effects of this chemical alteration that occurs. Methylation is the process of adding methyl groups to DNA. In humans, for example, approximately 1% of our DNA bases go through DNA methylation. This may not seem like a large amount, but if methylation did not occur, we may not look, act, think or behave the way we do as humans. Also, DNA methylation occurs in different types of tissues during different points of development. So if you take a skin cell from the ear to use for cloning an animal, the type of methylation would be different from an embryonic stem cell.

There’s also something else that’s interesting that occurs in cloned animals. There is a normal DNA methylation cycle that occurs during natural conception. However, in cloned animal, that normal cycle is disrupted and is actually a lot shorter than during natural conception. So, if all of the genes that are supposed to be methylated do not have time to be methylated, the constitution of the animal can be dramatically changed. Methylation is responsible to activating certain genes. This is why cloned animals may not look the same as their parents (by parent, I mean the animal they were cloned from). Temperamentally, cloned offspring can also be dramatically different from their parent and from other cloned offspring that may be their littermates.

 In swine, we have seen litters that all have the exact same genetic code but they look and act completely different. The DNA donor in one case had short hair and while some of the piglets had short hair, others had long hair. They varied in size and personality and there was no uniformity. This may be attributed to methylation.

Now, when we talk about the temperament and personalities of the cloned animals, we forget the factors that contribute to this. The environment plays a large role in how animals develop. Your star bucking bull is as good as he is because of his DNA and because of the conditions in which he was raised. We don’t know all of the factors that contribute to bucking at this point, but behavior does play a large role. Is it learned behavior from his mother? Is it the interactions with the other young bulls he interacts with? Was the nutrition the mother consumed during pregnancy a factor in the amount of methylation that occurred in utero? The clones will not be brought up under the same identical conditions of the DNA donor, and we cannot expect the clones to behave the same way.

So can cloning play a role in the bucking bull industry? The answer, even after everything I’ve covered, is yes. If you are trying to copy your top bucking bull, it is unlikely that you will produce one. If you want to replicate one of your top producing females or sires, you may consider investing in cloning. Just because the cloned animal will not perform like the DNA donor, there seems to be evidence that it will pass on its genes normally to its offspring. This could be used to reproduce CP47 genes, for example, to use for breeding purposes.

However, this leads me to my final point on cloning, and I’ve heard the cloning marketers tote this as a good thing: the decrease of genetic diversity that cloning leads to. This is not, as they claim, necessarily a good thing. This is something that can possibly be detrimental to the industry. The top bulls are combinations of many different breeds. How many bucking bulls are out there that are purebred Angus or Hereford? Rodeo stock has evolved from a lot of genetic diversity, and cloning limits that. Bucking appears to be a lowly heritable trait and, if that’s the case, the best way to increase bucking is through heterosis. This means you want to breed animals that are further apart genetically. You don’t want to breed fathers to daughters to create the same genes, you want to find animals more dissimilar.

Now that that’s been addressed you need to think about the different ways of cooperation. You can exchange bulls in order to increase the genetic diversity of the progeny, you can go in on in-vitro procedures with purchased semen from a third party and divide the offspring, and you can share embryos from top donors in your herds or any variety of situations.

While cloning is a great boost to science and can be beneficial, it is my personal recommendation that you do not use it as your primary means of producing high quality animals. You will serve yourself and your animals better by practicing good herd management, by selecting your breeding stock based on performance, by keeping good records to help you better identify your top producers and by outcrossing to known performers. The drive to produce better quality animals cannot be circumvented by using shortcuts.

That’s what many people may want to accomplish through cloning.