Multiple Alleles: Definition & Example

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Random Assortment of Chromosomes: Definition & Explanation

You're on a roll. Keep up the good work!

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:01 Variation in Nature
  • 1:02 What Are Multiple Alleles?
  • 3:15 Lesson Summary
Save Save Save

Want to watch this again later?

Log in or sign up to add this lesson to a Custom Course.

Log in or Sign up

Speed Speed

Recommended Lessons and Courses for You

Lesson Transcript
Instructor: Dominic Corsini
This lesson introduces the concept of multiple alleles. It provides the definition of multiple alleles and presents several examples of this type of trait within both human and animal populations.

Variation in Nature

In Pennsylvania, there is a local university that recently purchased a really cool new toy. That 'toy' is called a gene sequencer, and it cost them somewhere in the neighborhood of $100,000. However, despite the cost, the machine itself is really neat. It allows people to study genes on a molecular level and better understand how they work. A gene is a segment of DNA that spells out the genetic code for a particular trait. A trait is a physical characteristic. Let's look at an example of a fish.

This fish has traits for color pattern, fin shape, mouth shape, size, weight, etc. Now, do you suppose all the fish of this species are exactly alike in all ways? No way! They are all similar, but no two are exactly alike. That's because each fish has a unique combination of alleles. Alleles are different versions of a trait.

What Are Multiple Alleles?

Some genetic studies begin (and end) with an investigation into traits that only have two versions of an allele. Think middle school biology. In humans, this is limited to items such as ear lobes (attached vs. unattached), your hairline (widow's peak vs. non widow's peak), or some similar, less complex characteristic. But, life is rarely so simple. People have somewhere around 23,000 different genes! Most of these genes have more than two versions. In fact, several have many different versions. Consider all the different shades of hair that exist within a population. Or, take a look at something as familiar as your own eye color.

To unlock this lesson you must be a Member.
Create your account

Register to view this lesson

Are you a student or a teacher?

Unlock Your Education

See for yourself why 30 million people use

Become a member and start learning now.
Become a Member  Back
What teachers are saying about
Try it risk-free for 30 days

Earning College Credit

Did you know… We have over 200 college courses that prepare you to earn credit by exam that is accepted by over 1,500 colleges and universities. You can test out of the first two years of college and save thousands off your degree. Anyone can earn credit-by-exam regardless of age or education level.

To learn more, visit our Earning Credit Page

Transferring credit to the school of your choice

Not sure what college you want to attend yet? has thousands of articles about every imaginable degree, area of study and career path that can help you find the school that's right for you.

Create an account to start this course today
Try it risk-free for 30 days!
Create an account