Artificial Selection: What It Is, Types, And How It Works
The world is inhabited by approximately 7.7 billion inhabitants, of which (according to the World Health Organization) 690 million went hungry during 2019. It is a fact that global production and distribution of goods is completely skewed because On the other side of the coin, 1.9 billion people were overweight in 2016.
Population numbers are advancing rapidly and, unfortunately, food production chains are increasingly threatened by multiple processes: multi-resistant bacteria, lack of space, climate change and many other deleterious events for the population. livestock and agriculture. It is reasonable to think, therefore, that the “natural” characteristics of the beings we feed on are no longer sufficient.
Terms such as genetic engineering and artificial selection come into play here Human beings have modified or selected the genes of various species of living beings of agricultural, livestock or any animal with social interest (pets, pack animals, etc.) for their own benefit throughout history: we are not facing a new practice, but in the face of an increasingly aggressive expansion of it. If you want to learn more about artificial selection and what it entails, keep reading.
It is common for society to fear the “ghost” of change, since playing at being gods can seem dangerous in a world in which we still have much to know. The reality is that, for better or worse, human beings have distanced themselves from natural mechanisms for hundreds and hundreds of years.
To understand what artificial selection is, the first thing to clarify is what it is not, since it is common to attribute biased characteristics to this type of terms depending on the argument you are trying to put forward. With all the care in the world and leaden feet, we confront the term of artificial selection with others related to it in the following lines.
Artificial selection VS natural selection
Natural selection is defined as the evolutionary mechanism based on the differential reproduction of genotypes in a biological population Postulated by the famous biologist Charles Darwin, natural selection postulates that environmental conditions (whether biotic or abiotic, that is, the physical environment or caused by other living beings) favor or hinder the reproduction of species according to their peculiarities.
It is necessary to know that natural selection is not an infallible and perfect mechanism: living beings do what they can with what they have, which is why not all adaptations are the best in a given environment. In summary, all this evolutionary force is based on fitness : Living beings that present the most suitable characteristics in a given environment will live longer and, therefore, reproduce more and transmit their genes to subsequent generations.
It is also important to highlight that natural selection is not a unique force, since evolution is also biased by processes such as genetic drift, which are completely random and stochastic in nature.
On the other hand, Artificial selection, as its name suggests, does not respond to normal adaptive mechanisms in a wild environment We are facing an environment that is anything but natural, since it is characterized by developing in a largely anthropized environment where what interests us, human beings, is chosen.
Artificial selection VS genetic engineering
It is very common to observe a clear confusion regarding these two terms. It is time to define them both quickly and concisely to leave no possible room for doubt.
Genetic engineering can be summarized in the following concept: a discipline that encompasses a series of techniques that involve the direct modification of an organism’s genes for a specific purpose
On the other hand, artificial selection, despite the redundancy, is the selection of parents with one (or several) characters of interest, so that all possible descendants also present them and the desired trait spreads in the population.
It is shocking to know that, today, Only 27 types of transgenic crops are marketed and 95% of genetically modified animals are laboratory rats for purely scientific purposes The reality is that most of the foods that end up on our table are the product of artificial selection and not genetic engineering, since obtaining a transgenic animal is monetarily expensive, difficult and, today, a practice that is not common in the world. livestock field.
Types of artificial selection
As you may have seen, there is a clear attribute that differentiates artificial selection from the rest of the mechanisms: Here the human being chooses the best of what is already available, since it does not create new traits where there was no indication of them before
Thus, when we talk about a hen that lays many eggs, we are referring to the product of an extensive history of artificial selection where each time the most suitable laying parents have been selected, not a transgenic animal that has undergone genetic modification. It is very important to make this distinction because, although the term “transgenic” is fashionable, it is not at all as widespread as many people think.
Once we have left this forest of terminological doubts, it is also necessary to emphasize that there are several types of artificial selection. Based on the degree of planning, there are two types :
A clear example of conscious selection that is self-explanatory is that of dogs: breeds are the product of crossing and inbreeding, where individuals of interest are selected for sexual reproduction using specific criteria. On the other hand, and without abandoning the world of canids, the case of black wolves could be considered an unconscious artificial selection.
According to scientific sources, these black wolves belong to the same species as traditional gray wolves (Canis lupus), but it is speculated that their melanistic color arose from crossing with domestic dogs that had said gene. Thus, in this case the human being would be carrying out unconscious artificial selection: the characteristics of an animal population are indirectly (and unintentionally) modified.
On the other hand, Artificial selection can also be divided according to what is sought (or not) in the population of interest :
In our minds, we usually think of positive selection when talking about artificial selection: we choose the biggest tomatoes, the chickens that lay the most, the cows with the most meat and muscle. The reality is that, a rancher, when he sacrifices an animal with a genetic dysfunction, he is already unwittingly carrying out negative artificial selection. It is much more common to select living beings based on what is not wanted (diseases, birth defects, and other events) than to select them for their positive attributes.
Benefits and harms of this procedure
We cannot close this space without the obvious ethical connotations that artificial selection carries with it Among the clearest benefits of these techniques we can find the following:
Artificial selection allows a more harmonious coexistence between domestic species and human society.
Production capacity can be increased with the same space and number of individuals.
Sometimes, artificial selection allows certain species to persist over time, since they are in a controlled environment.
On the other hand, the disadvantages of all this are also more than clear: sometimes some populations become a shadow of what they were in the wild. Excessive inbreeding, for example, produces a weakening of the genetic lineage of the species and its evolutionary destiny : The descendants of this type of selection are more prone to suffer from certain diseases, anatomical difficulties, unpredictable mutations and a host of other problems. The reality is truly uncomfortable, since it is clear that a pug dog will never have the same health and evolutionary aptitude as a wolf.
And you do you think?
As you may have read in these lines, we are facing a rather thorny issue. It is clear that artificial selection entails multiple ethical dilemmas, because when is the modification of a species unjustifiable? To what extent can the evolutionary rope be tightened without breaking it? What is the limit of animal suffering that we are willing to encourage in order to increase productivity?
All these questions depend on the judgment and values of each and every one of the readers who have read these lines. There is no definitive answer, but one thing is clear: there are more and more people on the planet, and nature is no longer capable of supplying us. What to do from here is subject to personal judgment.
With hunger rising and malnutrition persisting, achieving zero hunger by 2030 is doubtful, warns a report from the United Nations, World Health Organization. Collected on December 13 at https://www.who.int/es/news/item/13-07-2020-as-more-go-hungry-and-malnutrition-persists-achieving-zero-hunger-by- 2030-in-doubt-un-report-warns#:~:text=In%20la%20%C3%BAltima%20edici%C3%B3n%20de,60%20million%20in%20five%20a%C3%B1os).
Artificial selection, undestandingevolution. Collected on December 13 at https://evolution.berkeley.edu/evolibrary/article/0_0_0/evo_30_sp
Lungarete, F. (2012). Artificial selection (Doctoral dissertation, National University of La Plata).
Soler, M. (2002). Evolution. Southern Editions Project: Granada.
