Mutations (Updated)

Summary

The video script delves into the concept of mutations, explaining them as changes in genetic material that can affect all organisms with DNA or RNA. It highlights that mutations are random and can be neutral, harmful, or beneficial. The script covers various types of mutations, including gene and chromosomal mutations, and how they can be passed to offspring. It uses examples like fruit flies and sickle cell anemia to illustrate mutation effects and inheritance. The importance of studying mutations for understanding genetic disorders and potential treatments is emphasized.

Takeaways

• 🧬 Mutations are changes in genetic material, specifically within nucleic acids like RNA and DNA.
• 🐞 All organisms with RNA or DNA, including animals, plants, fungi, and even viruses, can experience mutations.
• 🎢 Many mutations are neutral, neither harmful nor beneficial, and do not change an organism's traits.
• 🔄 Mutations are random and cannot be willed by an organism; they occur without intention.
• 💊 External and internal factors, such as chemicals, radiation, and issues during DNA replication, can increase the likelihood of mutations.
• 🌡 Gene mutations involve changes in DNA bases and can alter the proteins produced, affecting an organism's traits.
• 🔄 Frameshift mutations caused by insertions or deletions can dramatically change the reading frame of codons, affecting multiple amino acids.
• 🧬 Chromosomal mutations involve changes to the structure of chromosomes, such as duplications, deletions, inversions, and translocations.
• 🍇 Fruit flies are often used in genetic studies due to their ease of breeding and observable mutations.
• 🧫 Sickle cell anemia is a genetic disorder caused by a mutation in the gene coding for hemoglobin, affecting red blood cell shape and oxygen transport.
• 🩺 Studying mutations and genetic disorders is crucial for understanding and treating diseases, and careers in this field are valuable and in demand.

Q & A

What is a mutation?

A mutation is a change in the genetic material, more specifically, a change within a nucleic acid like RNA or DNA.

Which types of organisms can experience mutations?

Any organism with RNA or DNA can experience mutations, including animals, plants, fungi, protists, bacteria, archaea, and viruses.

Can an organism will itself to get a certain mutation?

No, mutations are random and an organism cannot will itself to get a certain mutation. It is not a conscious process.

What are some factors that can increase the likelihood of mutations?

External factors like certain chemicals or excessive radiation, and internal factors like issues with DNA replication during interphase can increase the likelihood of mutations.

What is a gene mutation and how can it affect an organism?

A gene mutation is a change in one or more DNA bases within a gene that can lead to the production of different proteins, potentially affecting an organism's traits.

What are the types of mutations that can occur within a gene?

Types of gene mutations include substitution, where the wrong base is matched; insertion, where an extra base is added; and deletion, where a base is removed.

What is a frameshift mutation and why is it dangerous?

A frameshift mutation occurs when a base is inserted or removed, changing the total number of bases and altering the reading frame. This can affect all subsequent codons and lead to significant changes in the amino acid sequence of the protein.

What are some examples of chromosomal mutations?

Examples of chromosomal mutations include duplication, where extra copies of genes are generated; deletion, where some genetic material breaks off; inversion, when a chromosome segment is reversed and reattached; and translocation, when a fragment from one chromosome attaches to another chromosome.

What is nondisjunction and how can it result in genetic issues?

Nondisjunction is when chromosomes do not separate completely during meiosis, leading to egg or sperm cells with an abnormal number of chromosomes, which can cause genetic disorders in offspring.

How can a mutation be passed down to offspring?

A mutation can be passed down to offspring if it is present in the genetic material of the sperm or egg cell, which then combines during sexual reproduction to form a new organism with the mutation.

What is sickle cell anemia and how is it caused?

Sickle cell anemia is a genetic disorder caused by a mutation in the gene that codes for hemoglobin, the protein in red blood cells that carries oxygen. This mutation affects the shape of red blood cells, making it difficult for them to carry oxygen and leading to anemia and other health problems.

Why are individuals with sickle cell trait less severely affected by malaria?

Individuals with sickle cell trait, who carry one copy of the mutated gene, have a protective factor against malaria because their partially altered red blood cells can resist the invasion by the malaria parasite, resulting in less severe symptoms.

Outlines

00:00

🧬 Understanding Mutations and Their Impact

This paragraph delves into the concept of mutations, explaining them as changes in genetic material, specifically within nucleic acids like RNA and DNA. It emphasizes that mutations can occur in all organisms, including animals, plants, fungi, protists, bacteria, archea, and viruses. The discussion highlights that many mutations are neutral, while others can be harmful or beneficial. The randomness of mutations is stressed, with no organism able to will a specific mutation. Factors influencing the likelihood of mutations are also mentioned, such as external chemicals, radiation, and internal factors affecting DNA replication. The paragraph further explores different types of mutations, including gene mutations that can alter an organism's traits through changes in DNA bases, and chromosomal mutations affecting the structure and number of chromosomes. The potential dangers of insertions and deletions, leading to frameshift mutations, are explained. The discussion concludes with the mention of meiosis as a vulnerable time for mutations and the possibility of these being passed to offspring.

05:02

🐝 The Awesome World of Fruit Fly Mutations and Human Applications

This paragraph focuses on the significance of fruit fly mutations and their inheritance, which are widely studied in scientific research. It explains that these studies are crucial as the mutations observed in fruit flies can also occur in humans. A specific example is provided, discussing sickle cell anemia, a genetic disorder caused by a mutation in the gene coding for hemoglobin. The paragraph outlines how inheriting two mutated copies of this gene results in the disorder, affecting the red blood cells' ability to carry oxygen. It also touches on the improved treatment options available and the protective role of being a carrier against malaria. The importance of studying mutations and genetic disorders is highlighted, mentioning the role of genetic counselors in aiding families potentially affected by such conditions. The paragraph concludes by encouraging viewers to stay curious about the fascinating world of genetics.

Keywords

💡mutations

Mutations refer to changes in genetic material, specifically within nucleic acids like DNA and RNA. These changes can occur in all organisms, including humans, animals, plants, and even viruses. The video emphasizes that mutations are random and can be neutral, harmful, or helpful, affecting an organism's traits and potentially leading to genetic disorders or beneficial adaptations. For example, the video discusses how a bacterium might have a mutation that allows it to survive an antibiotic, highlighting the role of mutation in evolution and adaptation.

💡nucleic acids

Nucleic acids, DNA and RNA, are the carriers of genetic information in living organisms. They are essential for the storage and transmission of genetic instructions for the development, functioning, and reproduction of all known living organisms and many viruses. In the context of the video, mutations occur within these nucleic acids, leading to changes in the genetic code that can affect an organism's traits and abilities.

💡silent mutation

A silent mutation is a type of genetic mutation where a base in the DNA sequence is altered, but the change does not affect the amino acid sequence of the protein produced. This means that despite the mutation, the function of the protein remains the same. An example from the video is a codon that codes for the amino acid leucine; even after a base alteration, it still codes for leucine, demonstrating that not all mutations lead to significant changes.

💡frameshift mutation

A frameshift mutation is a type of genetic mutation caused by the insertion or deletion of DNA bases, which shifts the reading frame of the genetic code during protein synthesis. This shift can result in a completely different and often nonfunctional protein, because the original codon sequence is disrupted. The video provides an example of how a single base insertion can alter all subsequent codons, leading to a drastic change in the amino acid sequence of the resulting protein.

💡chromosomal mutations

Chromosomal mutations involve changes to the structure or number of chromosomes, which can affect a large number of genes at once. These mutations can include duplication (extra copies of genes), deletion (loss of genetic material), inversion (reversal of a chromosome segment), and translocation (transfer of a chromosome fragment to another chromosome). Chromosomal mutations can have significant effects on an organism's traits and can lead to various genetic disorders.

💡nondisjunction

Nondisjunction is a process error that occurs during meiosis, where chromosomes do not separate properly into daughter cells. This can result in gametes (sperm or egg cells) with an abnormal number of chromosomes, either too many or too few. When such gametes participate in fertilization, it can lead to offspring with genetic abnormalities, such as having extra or missing chromosomes, which can cause various health issues and developmental disorders.

💡meiosis

Meiosis is a type of cell division that produces reproductive cells (gametes) with half the number of chromosomes of the parent cell. It is essential for sexual reproduction in organisms, ensuring that offspring have the correct number of chromosomes. The video mentions meiosis as a vulnerable time for mutations to occur due to the complex process of chromosome separation, which can result in nondisjunction if it goes wrong.

💡sickle cell anemia

Sickle cell anemia is a genetic disorder caused by a mutation in the gene that codes for hemoglobin, a protein in red blood cells responsible for carrying oxygen. The mutation leads to the production of abnormal hemoglobin, which causes red blood cells to become rigid and sickle-shaped, impairing their ability to transport oxygen and leading to various health problems. The video uses sickle cell anemia as an example of how a gene mutation can have significant health consequences.

💡genetic counselors

Genetic counselors are professionals who provide guidance and support to individuals and families who may be at risk for genetic disorders. They help interpret genetic information, communicate the risk of these disorders, and provide advice on testing and management options. In the context of the video, genetic counselors are mentioned as part of the broader field of studying mutations and genetic disorders, highlighting their role in supporting those affected by such conditions.

💡fruit flies

Fruit flies, specifically Drosophila melanogaster, are model organisms extensively used in scientific research due to their short life cycle, ease of breeding, and the similarity of their genetic makeup to humans. The video frequently mentions fruit flies as they are often used to study the principles of genetics, including mutation and inheritance, providing valuable insights that can be applied to understanding human genetics.

💡malaria

Malaria is a disease caused by a protist called Plasmodium, which is transmitted to humans through the bite of infected mosquitoes. Individuals who are carriers of the sickle cell gene mutation have a protective factor against malaria, as the video explains. While they can still contract the disease, their symptoms are often less severe, demonstrating how certain genetic mutations can provide some resistance to specific diseases.

Highlights

Curiosity about mutations since childhood, influenced by movies and imagination.

Mutations are changes in genetic material, specifically within nucleic acids like RNA and DNA.

All organisms with RNA or DNA, including animals, plants, fungi, protists, bacteria, archea, and viruses, can experience mutations.

Many mutations are neutral, not changing the amino acid coded by a codon even when a base is altered, known as a silent mutation.

Mutations are random and an organism cannot will itself to acquire a specific mutation.

Factors like chemicals, radiation, or issues in DNA replication can increase the likelihood of mutations.

Gene mutations involve changes in DNA bases, affecting the proteins coded by genes and thus an organism's traits.

Types of gene mutations include substitution, insertion, and deletion, which can lead to frameshift mutations affecting codon reading.

Chromosomal mutations involve changes in the structure or number of chromosomes, such as duplication, deletion, inversion, and translocation.

Mutations can occur during DNA replication or meiosis, leading to nondisjunction and changes in chromosome numbers in gametes.

Inheritance of mutations can occur in both asexual reproduction, as seen in protists, and sexual reproduction, as in fruit flies.

Studying fruit fly mutations and inheritance is a common practice in research due to their simplicity and efficiency.

Gene mutation example: Sickle cell anemia is caused by a mutation in the gene coding for hemoglobin.

Individuals with sickle cell anemia have difficulty carrying oxygen due to the shape of their red blood cells being affected.

Sickle cell anemia treatment has improved, and carriers of one mutated gene are often protected against malaria.

Studying mutations and genetic disorders is crucial, and genetic counselors help families potentially affected by such disorders.

The importance of staying curious and continuing to learn about the complexities of genetics and mutations.

Transcripts

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.