Mutations (Updated)


Captions are on! Click CC at bottom right to turn off. Ever since I was a kid, I have been curious
about mutations. I think certain movies may have had an impact;
I used to imagine mutations with amazing abilities. But, there was also a lot I didn’t understand. Let me explain. Many people understand that a mutation is
a change of genetic material—more specifically a change within a nucleic acid. RNA and DNA are both types of nucleic acids. Therefore, anything with RNA or DNA can have
a mutation. That means animals- and that definitely includes
humans- also plants, fungi, protists, bacteria, Archeaa- they can all have mutations. Additionally, so can viruses. Many mutations can be neutral in effect. You can see this codon codes for the amino
acid leucine. But if it experiences this particular silent
mutation, even though a base has been altered, it still codes for leucine. It did not change the amino acid. Mutations can also be harmful or helpful. But it’s important to understand that mutations
are random. The organism can’t “will” itself to
get a certain mutation. You can learn more about this in our natural
selection video where we talk about how a bacterium may already possess a helpful mutation
that allows it to survive an antibiotic, but the bacterium didn’t “will” itself to
mutate to get this certain mutation. Ok, so again, mutations are random. But there can be factors that can make mutations
more likely to occur. External factors like certain types of chemicals
or excessive radiation or internal factors like an event that causes a problem with DNA
replication in interphase. During interphase, cells can replicate DNA
before they divide. So let’s discuss some different types of
mutations. We’ll start with gene mutations. DNA makes up genes and genes can code for
proteins that influence different traits. So when a mutation in DNA happens, which specifically
means a change in one or more DNA bases, then different proteins can be produced which can
affect an organism’s traits. In this example, we have fruit fly DNA. Mutations could include substitution which
means the wrong base is matched. Insertion, which means an extra base (or bases)
are added in. There is also deletion, which means a base
is removed. Insertions and deletions have the potential
to be especially dangerous. Why? Remember in protein synthesis, how we talked
about how bases are read in threes? Well if you add a base or remove a base, suddenly
the number of bases total has changed. And if you read the bases in threes—depending
on where it happened—- everything that is read afterwards could be affected. We call this a frameshift mutation. If you look at this frameshift example here
where a single base has been inserted, you can see now how the following codons—which
have 3 bases each—are now all affected as the reading frame has been shifted. This example shows how it can lead to many
amino acid changes. There are also chromosomal mutations. Remember that chromosomes are made up of DNA
and protein—-highly organized—and they have lots of genes on them. The human chromosome number is 46 with 23
from an egg cell and 23 from a sperm cell. This type of fruit fly here, however, has
8 chromosomes so 4 came from an egg cell and 4 came from a sperm cell. Some examples of chromosomal mutations include
duplication, where extra copies of genes are generated. Deletion, where some of the genetic material
breaks off. Inversion, when a broken chromosome segment
gets inversed (which means reversed) and put back on the chromosome. Or translocation when a fragment from one
chromosome breaks off and attaches to another chromosome. There’s more mutations than what we covered
of course, but the idea is that there are many different kinds of changes that can happen. If a mutation is going to happen, we already
mentioned that there are especially vulnerable times such as during DNA replication but also
there are other times too…like meiosis. In fruit flies and other animals, meiosis
makes sperm and egg cells that can have half the number of chromosomes as the organism. However, sometimes those chromosomes don’t
separate completely. We call this nondisjunction. This can result in an egg or sperm cell that
has too many or too few chromosomes. It’s possible for a mutation to be passed
down to an offspring. Consider a protist with a mutation. Many protists reproduce asexually, and when
they divide, the daughter cell can inherit the same mutation. A fruit fly, which reproduces sexually, can
pass a mutation to its offspring if that mutation is found in the genetic material of the sperm
or egg cell. You may wonder why we’ve been mentioning
fruit flies so much? Well, they’re AWESOME. But, also, it turns out that fruit fly mutations—and
how they are inherited—are frequently studied. We have some links in the video description
for more info. These studied mutations can also occur in
humans, and we’ll give a gene mutation example of a substitution in the case of sickle cell
anemia. First- a little background. Hemoglobin is a protein in your red blood
cells that helps you carry oxygen. But in the disorder sickle cell anemia, the
gene that codes for hemoglobin is mutated. If you inherit two copies of this gene (one
from each parent), you can have this disorder. This disorder can make it difficult for your
red blood cells to carry oxygen because the shape of the red blood cell is affected from
this mutated hemoglobin protein. This can lead to anemia and other problems. While unfortunately there is not a cure for
this disorder yet, the good news is that treatment for this disorder has greatly improved. Another thing to mention, if an individual
only inherits one copy of the mutated gene from one parent, they are a carrier but they
don’t officially have the disease. Usually they do not have symptoms. But those that are carriers appear to have
a protective factor against malaria. Malaria is a disease caused by a protist that
can be transmitted by mosquitoes. These individuals can still get malaria, but
their symptoms are often less severe. We should mention that studying mutations
and genetic disorders is a large and important field right now. Genetic counselors work to help families that
may be affected by genetic disorders. If you have an interest in learning more about
careers related to this topic, please check out some of our further reading suggestions
in the description below. Well, that’s it for The Amoeba Sisters,
and we remind you to stay curious.

48 thoughts on “Mutations (Updated)

  1. You guys are the best though, you make hard concepts seem super easy, you helped me with pre-AP bio and Iโ€™m sure will with AP bio this year! Thank you.

  2. We hope you like our newly updated Mutations video! So what is different? You will find the script to be almost the same, although we think we improved explaining a silent mutation and a frameshift mutation. We also emphasized that mutations can happen in all kinds of organisms (and viruses too)! [Pinky wanted to add that emphasis as she found students were surprised to learn mutations occur in plants and protists!] Our art has also improved as we continue to practice. No MS Paint this time โ‰งโ—กโ‰ฆ! You can see our milestones here: https://www.amoebasisters.com/milestones We did decide to create an updated free student mutation handout—we don't always update old video handouts, but we wanted to improve it: https://www.amoebasisters.com/handouts Still prefer the old video (and handout)? No worries! We try to not delete old videos and you can find it here: https://youtu.be/GieZ3pk9YVo

  3. Itโ€™s summer vacation and Iโ€™m not taking biology anymore, but Iโ€™m still gonna watch this ๐Ÿ˜‚

  4. I am from India and I am in love with u ,I don't know how I will leave without u sisters ๐Ÿ˜‹๐Ÿ˜i m anannya๐Ÿฅฐ

  5. Im on vacation but I'll watch it only to see sickle cell disease as an example ๐Ÿ˜‚๐Ÿ˜‚it's always there

  6. Even though Iโ€™m on summer break, I still love to watch your videos, cause they are entertaining and fun. You guys are able to explain certain concepts better than my teacher, and I thank you for that

  7. Yay! More science!

    Today mom looked at me weird because I was talking about DNA replication and 5 prime to 3 prime.

    Thank you!!!!! โค๏ธ

  8. I love watching your videos because I love science in and out of school keep up making amazing science videos

  9. I showed this to my younger brother and he loved how well explained it is and the drawing which helped him understand a lot more than how his teacher explained. Thanks <3

  10. I love your videos and the little cells are all so cute. Your videos got me through Grade 11 Bio. Many thanks!

  11. I will admit that I have fell asleep during these videos when my teacher would play them but now I'm watching them because I can't sleep

  12. There are hopeful trials now to use CRISPR gene editing to cure sickle cell anemia in the news this week. See:

    https://www.physiciansweekly.com/trial-tests-crispr-gene-editing-to-treat-sickle-cell-disease/

  13. Hi. Can someone help me?

    Im kind of confused, so a chromosome is made up of DNA? And DNA is made up of genes? So if weโ€™re going to arrange them into order, chromosomes > dna > genes?

  14. Thank u so much…teachers can just confuse us…but m so happy that u help me clear all my confusions… u make the hardest of topics seem so easier.

  15. Just wanted to say THANK YOU for making these videos! I watched everyone of them before taking the Biology CLEP test today (which I passed), and I can truly said they helped me immensely! You have a way of simplifying concepts to make them easy to understand. And I used a lot of your memory tips too! Thanks!

  16. Im so glad you guys are making videos again! This helped me through college and now im in med school, and find that for a quick review before reading the biochem book, your videos are great. you should make one about antibodies, structure, types and functions!

Leave a Reply

Your email address will not be published. Required fields are marked *