Mutations | Genetics | Biology | FuseSchool

Summary

Mutations are changes in DNA that can alter genes and proteins, impacting an organism's traits. While most mutations are neutral, some drive genetic variation, fueling evolution through natural selection. External factors like radiation and chemicals can cause mutations, sometimes leading to diseases like cancer. For instance, antibiotic-resistant bacteria evolve rapidly, posing challenges in medicine. This video explores how mutations work, their role in genetics, and their potential effects on organisms, from phenotype changes to health risks, offering insight into the complex processes that shape life and survival.

Takeaways

• 😀 Mutations are changes in DNA that occur when nucleotides are deleted, inserted, or substituted.
• 😀 Mutations can alter the sequence of nucleotides, potentially changing the shape of proteins and how they function.
• 😀 A mutation in a gene that codes for an enzyme can affect the enzyme’s ability to function properly, for example, by misfolding the protein.
• 😀 Only 1% of human DNA codes for proteins; the rest is non-coding DNA, which can regulate gene expression.
• 😀 Mutations can also happen in areas of DNA that control gene expression, affecting whether proteins are made or not.
• 😀 Most mutations have no effect on the phenotype, as they occur in non-coding regions or do not affect gene expression.
• 😀 Genetic variation, such as differences in hair, skin color, or eye color, is the result of mutations over generations.
• 😀 Natural selection drives the spread of advantageous mutations in a population, such as improved hearing or better survival traits.
• 😀 Mutations can lead to antibiotic resistance in bacteria, which is a major concern for human health.
• 😀 Mutations can be caused by external factors like ionizing radiation (e.g., UV rays, X-rays) or chemical mutagens (e.g., tobacco smoke).
• 😀 Exposure to radiation can increase the risk of cancer by affecting DNA regions that control cell division, leading to uncontrollable growth.

Q & A

What is a mutation in DNA?

A mutation is a change in the DNA sequence, which occurs when one or more nucleotides are deleted, inserted, or substituted for a different nucleotide.

How do mutations affect proteins?

Mutations can alter the sequence of amino acids in proteins by changing the order in which they are coded, potentially changing the shape of the protein. This can cause the protein to function differently or not work at all.

What role does non-coding DNA play?

Non-coding DNA makes up the majority of our DNA and does not code for proteins. However, it plays a role in controlling gene expression and regulating when and how genes are expressed.

Why do mutations in non-coding DNA matter?

Mutations in non-coding DNA regions that control gene expression can alter how a gene is expressed, potentially leading to changes in the phenotype, even if no new protein is produced.

How common are mutations and what is their impact on phenotype?

Most mutations occur in regions of DNA that do not code for proteins or control gene expression, meaning they have no impact on the phenotype. However, when mutations do affect protein function or gene expression, they can result in noticeable changes.

Can mutations lead to beneficial traits?

Yes, mutations can lead to beneficial traits that increase an organism's chance of survival. For example, a mutation in a population of mice that leads to white fur could be disadvantageous in the wild, but if a mutation provides a survival advantage, like better hearing, it may be passed on to future generations.

What is natural selection and how does it relate to mutations?

Natural selection is the process by which traits that provide a survival advantage are more likely to be passed on to offspring. Mutations that offer advantages, like enhanced sensory abilities, are more likely to increase in frequency in a population.

How do mutations contribute to antibiotic resistance in bacteria?

Mutations in bacteria can randomly provide resistance to antibiotics. Since bacteria reproduce quickly, advantageous mutations can spread rapidly through a population, leading to the evolution of antibiotic-resistant strains.

What are some common causes of mutations?

Mutations can be caused by exposure to ionizing radiation (e.g., gamma rays, x-rays, ultraviolet rays), certain chemicals (e.g., tobacco), and other mutagens that damage DNA and increase the risk of mutation.

How can exposure to radiation cause cancer?

Exposure to ionizing radiation can cause mutations in regions of DNA that control cell division. This can result in uncontrolled cell division, leading to cancer. For example, UV light is a known risk factor for skin cancer, and smoking increases the risk of lung cancer.