Chromosomal Rearrangement

An error occurred trying to load this video.

Try refreshing the page, or contact customer support.

Coming up next: Genetic Variability and Random Mutation

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 Chromosomal Rearrangements
  • 0:30 Deletions & Duplications
  • 2:50 Inversions & Translocations
  • 6:35 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: Artem Cheprasov

Artem has a doctor of veterinary medicine degree.

Have you ever switched out one thing for another or traded places with someone? Our chromosomes can do this, too. This lesson tells you how as we go over chromosomal rearrangements!

Chromosomal Rearrangements

Genetics can be boring. Unless, that is, we make it a participatory event. So assuming you have a pen and pencil or laptop next to you, let's play along together as we go over four different kinds of chromosomal rearrangements. These are chromosomal abnormalities where a chromosome's structure is reorganized through deletions, inversions, translocations, or duplications - all of which will be defined in due course.

Deletions & Duplications

Okay, using the laptop or pen and paper in front of you, let's type or write out the following: ABCDEFG. This whole string will represent a chromosome, with the individual letters representing genetic material within that chromosome.

Now go ahead and delete or cross out the D so that we're left with ABCEFG. That is, quite simply, a deletion, or a rearrangement that results in the removal of a segment of DNA, our genetic material. If the deletion occurs within a chromosome, like in our example, it's termed an interstitial deletion. If a deletion occurs at the end of a chromosome, we call this a terminal deletion. This would be like if we'd deleted the G in ABCDEFG instead of the D.

Okay. Now let's take that original whole chromosome of ABCDEFG and let's add in an additional BC right after the original BC to get ABCBCDEFG. What is this? This is a duplication, a rearrangement that results in an increase in the number of copies of a segment of chromosome. If the duplicated segments are located next to one another, as in our example, this is known as tandem duplication. This can occur in the same order, as in ABCBCDEFG, or in reverse order, as in ABCCBDEFG.

If the duplicated copy is found in a different region of the same chromosome or in another chromosome, we call this an insertional duplication. In our prior example, that would be like ABCDEFG turning into ABCDEFBCG, where the new BC is found in between F and G instead of right after the original BC.

Inversions & Transcolations

Okay. Let's get back to our original chromosome, ABCDEFG, and then let's tinker with it again. If you take ABCDEFG and flip BCD 180 degrees, what will you get? ADCBEFG. This is an example of an inversion, which is a rearrangement where a segment of chromosome is removed, rotated 180 degrees, and inserted into the same spot.

There are two types of inversions: paracentric and pericentric. To understand this, we need to rewrite ABCDEFG a little bit. Let's put a little dash in between ABC and DEFG, giving us ABC-DEFG. The dash in between ABC and DEFG represents the chromosome's centromere. The centromere is, quite simply, the part of the chromosome connecting chromatids together.

Now, if the inversion includes the centromere, we call this a pericentric inversion because 'peri-' means around or about. An example of this would be ABC-DEFG turning into AD-CBEFG. Note how the dash, representing the centromere, has moved because we inverted the segment BC-D 180 degrees into D-CB. If the inversion doesn't include the centromere, we call this a paracentric inversion because 'para-' means apart from or beyond. This would be like ABC-DEFG turning into ABC-DFEG, where the segment EF is reversed into FE.

And finally, let's rewrite everything back to our original ABCDEFG. Then, next to this, let's write in HIJKLM to represent a non-homologous chromosome. Non-homologous just means that it's a chromosome that's not of the same pair as the first one. This means we have:


But what if we turn this into the following?


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