Discover More: Domestication
Humans have used their brains to transform the world around them, overhauling landscapes, mass-producing materials and editing ecosystems beyond recognition. Discover more with Linnean Learning.
Published on 12th July 2021
The Discover More series is a collection of animations, blogs and interviews exploring a wide variety of topics to enrich your appreciation of the wonderful natural world that we are a part of. There are seven topics which will be released throughout 2021 and the animations are best viewed via Instagram @LinneanLearning.
Humans have used their brains to transform the world around them, overhauling landscapes, mass-producing materials and editing ecosystems beyond recognition. From dogs to wheat, we have formed unbreakable bonds with numerous species, selectively breeding them for traits that benefit our species in that moment, and often discovering unexpected results along the way.
This month we are highlighting how humans have domesticated nature, including ourselves. We’ll be talking with expert Maria Chacon from the National University of Colombia about the domestication of plants, in particular the Lima bean, Phaseolus lunatus. Read a couple of domestication examples below, watch our short animations on Instagram, Twitter or TikTok and enjoy our interview with Maria on those platforms or as a transcript (see below).
Let’s talk about bees. The western honey bee is one of the few invertebrate animals to have been domesticated by humans, and there is evidence, based on rock art, that this goes back as far as 7000BCE. These bees were likely first domesticated in ancient Egypt. Beekeepers have selected them for a number of desirable traits, including: resistance to cold; surviving long periods without food; resistance to disease; increased honey production; reduced aggressiveness; reduced tendency to build nests. These adaptations have improved the bee from the perspective of the beekeeper and meant the bees have become increasingly dependent on human partners for survival. Un-bee-lievable!
Our next example is close to our hearts. The banana. The Musa genus is varied and exciting, but most westerners just engage with a particular variant called the Cavendish banana, which has been selectively bred to be tasty, well textured and resistant to disease. However, the Cavendish banana only became popular in the 1950s after the main banana of the time, the Gros Michel banana, struggled with a fungal infection.
However, growing practices of these bananas are still… bananas! There is a very low genetic diversity in the bananas we eat which makes them prone to being easily wiped out by a new disease.
Our final example for now is of man’s best friend - our oldest companions - dogs. The domestication of dogs has had a huge impact on their ecology and evolution, and our own too. Dogs are, in essence, domesticated wolves - though the wolf species that they were domesticated from is now thought to be extinct. It is unclear how exactly humans first domesticated this wolf species but some think it was through hunting side-by-side and sharing kills. Over a long period of time, human-dog relationships became closer until humans began actively breeding dogs for tasks like hunting, pest-control, protection, herding, companionship, or… looking cute?
An interview to an expert in the domestication of nature
We spoke with Maria Chacon from the National University of Colombia about the domestication of plants, in particular the Lima bean, Phaseolus lunatus.
The following text is an edited interview between Monica and our Research Officer, Zia. Recorded interview coming soon.
It's great to get some time you Maria. Can I ask you to introduce yourself?
Yeah, my name is Maria Chacon. I was born in Colombia. I grew up in Cali, a town that is in southern Colombia. I studied biology and afterwards, I went to England to study a PhD in agricultural botany at the University of Reading. And then I came back to my country. Now I am a professor at the National University in Colombia here in Bogota.
Could you describe to us briefly, what is domestication?
Domestication can be defined as an evolutionary process by which crops and domestic animals originated during domestication. Wild plants and wild animals became better and better adapted to the environment provided by humans - for example, for plants, that would be the cultivated field. To the point that some plants or animals, they completely depend on humans for their own survival. But at the same time, we humans became more and more dependent on crops and domestic animals. So for that reason, some scientists say, and I say, that domestication is a co-evolutionary process. Plants, crops and domestic animals were, and are, and will be, very important for our survival.
You look at domestication in your work. Could you go into detail about what you research in relation to domestication?
Yeah, my research is about plant domestication. And namely, and we look at where crops originated - for example, the geography of domestication. We are also interested in knowing the effect that domestication has on the genetic diversity of crops. And we also want to know, what genes control all those traits that have changed during domestication. So I'm interested in that field basically.
We carry out comparative analysis. So we analyse different threats, on DNA sequences, in wild ancestors and their crops to understand the genetic diversity, first of all, and then also to understand how the wild populations are organised, in genetic terms - for example, if there are different wild populations. And also we look at the crop to which a wild population is most related, in order to be able to say, the place where that crop originated, for example, and to be able to say how many times the crop was domesticated, for example, to be able to identify regions in the DNA that could contain genes that control all those traits that have changed during domestication? So we were interested in, you know, in doing research about that.
What's the value in rediscovering where they come from?
During domestication crops lost a great amount of genetic diversity. And why? Because if we have different wild populations in the wild ancestor, not all of them were domesticated. Only one or two maybe. So the crop doesn't include all the genetic background of the wild ancestor. Apart from that, the breeding activities, erosion, all diversities fall down and fall down. So sometimes we need to go back to wild ancestors to recover all those alleles that were lost, or were not included in the initial domestication. So that's why it's important to study wild ancestors as well. A gene may have different sequences in one population, and an allele is one of those different sequences in the population.
Do you look at any particular species?
Yeah. In our research group we are interested in plant domestication. And we took as a model bean species, and not the common bean, but a very related species, Lima bean. We've been having some exciting results recently. So we were able to sequence the genome of one variety from Colombia, actually, from Northern Colombia, which grows in very dry areas. This is a very interesting crop, because he grows in different environments. So it's adapted to the wide range of environments. And we were able to identify the genetic structure in the wild, we were able to confirm that these bean was domesticated not only once but twice. Once in Mexico, and another time in the Andes in South America. Yeah, and now that we have this sequence in our hands, of the genome, we want to look at the genes that were important for the domestication process, and other genes for traits that are very important for breeding purposes.
You've been able to pinpoint these beans that have spread to many different regions, and pinpoint where exactly they might have been domesticated. It's really interesting to hear that they're really quite adaptable to different kinds of conditions. Is that important in relation to thinking about crops for the future?
Yeah, sure. In the wild, especially in Mexico, this species lives in all the ecological areas, you can find it near to the seaside, in very low altitude, very rainy areas, and also in very high altitude in the Andes. So it explores all kinds of ecological environments. That's why its a very interesting species, because we are pretty sure it contains alleles that may be useful, not only for Lima bean breeding, but for breeding other legume species.
You mentioned that there's a co-evolutionary dynamic in a lot of domestication, and I wondered how you would respond to the idea that the process of domestication is a part of human nature?
Yeah. I think so. Every time humans domesticate one species, they are interfering in their evolutionary trajectory. And I think humans are always interfering in, or trying to modify, the environment. So I think that makes it part of human nature.
About the number of domesticated species, I think that, in proportion to the amount of species that we have available, humans have only domesticated a small part of that. So In plants, for example, for flowering plants, we have about 300,000 species and humans have domesticated only a little more than 2,000, and that's less than 1%. So that's seen as a very small proportion. The good news is that we have many more species to look at, for overcoming our future challenges that we could have.
Did it always feel like a very easy and natural route for you being a scientist?
I was very fortunate that, when I decided to study biology, I got the support of my family. Because there are other careers that maybe parents want their children to study - for example, medicine - but my father, especially, he understood the importance of science. And I know that in Colombia, many people don't understand the importance of science so I know that for many people, this is a difficult decision to make. And after that, after I finished biology, I wanted to do a PhD overseas but the main difficulty is funding. I was very fortunate to have a scholarship from the Colombian government so I could make my PhD and then come back to contribute to society. Now that I'm a professor at the University, I'm still struggling with funding! Yeah, mainly, because the human talent is here but we need more investment for science.
Could you name some of the best things about being a scientist or being interested in science?
Yeah, I think that one of the best things is to be able to create scientific knowledge - for me, it's amazing. I mean, it's a satisfaction. I think all scientific knowledge is of benefit for society - for example, to solve problems, different kinds of problems, to improve the quality of life, and to improve the educational system of one country, and things like that. So I think this is the most important thing.
Thank you for sharing your insights into the domestication of nature today Maria, and particularly your optimistic view of the role of science in society.