Gametic Isolation: Definition & Example

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Genetic Manipulation: Definition, Pros & Cons

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

Take Quiz Watch Next Lesson
Your next lesson will play in 10 seconds
  • 0:02 Hybrids
  • 0:44 Prezygotic Barriers &…
  • 2:34 Examples
  • 3:35 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: Julie Zundel

Julie has taught high school Zoology, Biology, Physical Science and Chem Tech. She has a Bachelor of Science in Biology and a Master of Education.

Have you ever wondered why two separate species cannot mate and produce offspring? This lesson will examine the prezygotic barrier called gametic isolation and explain why interspecies cannot mate. It will also give some examples of organisms that experience gametic isolation.


What do ligers, zebroids, grolars, and wholphins all have in common, other than silly-sounding names? These are all hybrids, or the result of a mating of two different species, or interspecies mating. But interspecies offspring like ligers (tiger + lion), zebroids (zebra + horse), grolar (polar bear + grizzly), and wholphins (whale + dolphin) are not the norm in the world of organisms.

The term 'hybrid' can also mean the cross between different varieties within a species but for this lesson, we'll use it to mean a cross between two separate species.

Prezygotic Barriers and Gametic Isolation]

Typically, only members within a species can mate. In fact, a species is defined as a group of organisms that can interbreed or exchange genes. There are many barriers that prevent mating between different species, all of which can be divided up into two categories: prezygotic barriers and postzygotic barriers. Prezygotic barriers prevent animals from mating or, if mating occurs, prevent the sperm from fertilizing the egg. This is not to be confused with postzygotic barriers, or barriers that occur after fertilization.

Gametic isolation is a type of prezygotic barrier. Gametic isolation happens when the egg and sperm are released but a zygote is not formed. A zygote is the cell produced when an egg and sperm unite. The term 'gamete' refers to the reproductive cells like eggs and sperm.

Other prezygotic barriers prevent organisms from coming into contact with each other; they may live in different habitats, have different mating seasons, or perform different mating rituals. In cases of gametic isolation, however, the animals do come into contact, but the gametes (reproductive cells) are not compatible.

There a couple of possible reasons why the egg and sperm cannot unite in cases of gametic isolation. One is that sperm and eggs have specific proteins on their surfaces that allow the sperm to recognize the egg (and vice versa) and these proteins differ from species to species. So, if two different species mate, the sperm may be unable to recognize the egg. Another example of gametic isolation happens when the sperm is unable to survive or will be less mobile in the reproductive tract of a female from a different species.

Wow! That was a lot of vocabulary and information! Let's delve into the reproductive lives of sea urchins and coral to see gametic isolation in action.

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