Selective Breeding — Definition & Examples

What's Selective Breeding?

Selective breeding, also known as artificial selection, is the process of breeding organisms to create offspring with selected, desired traits. It's different from natural selection because the traits that we find desirable are typically not the ones that are beneficial to the organism in its normal environment. Choosing traits in this way allows us to take advantage of natural genetic variation. It's usually done with items of economic importance like crops and certain animals. For example, fish are often placed in selective breeding programs to increase their growth rate and meat quality.

Almost all domestic animals and plants we have are the result of thousands of years of artificial selection. Broccoli, cabbage, cauliflower, and kale are all selectively bred descendants of the wild mustard plant. Wild tomatoes were about the size of blueberries before we selectively bred them to be much larger.

Interestingly enough, the dog is believed to be the first animal our ancestors selectively bred, dating back to around 32,000 years ago. That's before humans figured out how to make rope.

For the bulldog, we continually bred dogs with short statures and loose skin until they resembled the modern dog we all know. Unfortunately, this sort of breeding often leads to health problems because the gene pool for the desired look can be very small. After many generations of selection, genetic problems can pile up.

How Is This Different From Genetic Engineering?

What's the difference between this type of breeding and genetic engineering? They have the same goal, to create useful phenotypes, but the term "genetic engineering" is usually used to describe technology that reaches this goal. One example is inserting genes from fireflies into mice, making them glow. Breeding selectively, on the other hand, uses reproduction to change the characteristics of a population over time.

We also tend to call genetically engineered organisms "genetically modified organisms", a label we don't usually give to selectively bred organisms.

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$\color{#8925AE}{\text{Genetic Engineering}}$ : The process of changing the genetic material of an organism

$\color{#8925AE}{\text{Selective Breeding}}$ : Also called artificial selection, this is the process of breeding organisms to create offspring with desired traits

$\color{#8925AE}{\text{Cloning}}$ : Creating a genetically identical copy of an organism

$\color{#8925AE}{\text{Genetically Modified Organisms}}$ : Organisms that have had their genome altered in some way

$\color{#8925AE}{\text{Gene Therapy}}$ : Inserting normal genes in place of missing or defective ones to fix genetic disorders

Controlling Phenotypes

Selective breeding is about controlling the phenotypes of offspring. This is usually done so that traits that people find favorable, like tastier corn or greener palm trees or faster dogs, are bred to make them more common in a population. Phenotypes can be tracked through multiple generations with a pedigree chart.

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(Video) Selective Breeding

by FuseSchool - Global Education

Artificial selection is the most ancient method of genetic engineering that humans have. We have been selectively breeding our pets, crops, and livestock for thousands of years.

In the video above, FuseSchool explains how the process works.

Artificial Selection

Selective breeding is the process by which you take organisms with desirable traits and breed those together in order to produce an offspring with this same desirable trait. This is based on the idea that traits are passed from parent to offspring. These traits can be tracked through multiple generations with a pedigree chart.

Humans have been using this technique since the dawn of civilization to breed animals and plants. The picture below is an example of what bananas looked like before they were domesticated by humans. This is a great example of plant breeding. Originally, this fruit was not very tasty. It had large, hard seeds and not that much fruit. So, humans took the plants which produced smaller and softer seeds with more edible fruit and bred them together.

Over many years of selection, the average size of the seed decreased as well as how much edible fruit there was, leaving us with the modern-day banana.