What Is Genetic Variation? - Sources, Definition & Types

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  • 0:04 What is Genetic Variation?
  • 1:15 Sources of Genetic Variation
  • 2:17 Lesson Summary
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Lesson Transcript
Instructor: Sarah Friedl

Sarah has two Master's, one in Zoology and one in GIS, a Bachelor's in Biology, and has taught college level Physical Science and Biology.

Natural selection is the process that drives evolution, but what drives natural selection? Genetic variation increases the genetic diversity in and among populations, allowing for new traits to become more or less prominent in the gene pool.

What is Genetic Variation?

Take a look at your family. You probably look similar to your parents and siblings, and they look similar to their parents and siblings. However, you don't look exactly the same, and this is due to genetic variation.

You get your genes from your parents, which is why you and your siblings look similar to them and each other. Your genes have alleles, which are different forms of the same gene. Alleles are like a code for your body that determine hair color and eye color, height, and other genetic features.

Genetic variation is the variation in alleles and genes, both within and among populations. Think of a population as a family unit. Within your family of closely-related individuals there is genetic variation. Within a neighborhood, there are many families, and so there is also genetic variation among that larger group.

Genetic variation can be identified through either continuous or discrete traits. Continuous traits are traits that vary continuously, such as height and weight. Discrete traits are traits that can only be measured discretely, such as tongue rolling; you either can or can't do this!

Sources of Genetic Variation

There are three sources of genetic variation: mutation, gene flow, and sexual reproduction.

A mutation is simply a change in the DNA. Mutations themselves are not very common and are usually harmful to a population. Because of this, mutations are usually selected against through evolutionary processes.

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