Mutation Summary Questions

Read the following notes and be prepared to answer the following questions.

1. Where would the child have gotten this trait?
2. Do you think this trait is beneficial to this baby?
3. What are the three ways a mutation can affect an organism?
4. How does a mutation occur?

Mutations

This baby was born with 2 thumbs on one hand. This trait was not inherited (passed down from parents).

Where would she have gotten this trait?

Do you think this trait is beneficial to this baby?

Mutations

Genetic mutations may result in harmful, beneficial, or neutral effects to the structure and function of the organism.

• Your DNA controls your traits.
• Changes in the structure of your DNA, called mutations, could cause changes to your physical traits or affect how certain body parts function.

Mutations

The process of DNA replication before a cell divides is not always 100% accurate.

• Sometimes the wrong code is inserted in the new strand of DNA.
• This wrong code could become permanent.
• A permanent change in the sequence of DNA is known as a mutation.
• Once DNA has a mutation, that mutation will be copied each time the DNA replicates.
• After cell division, each resulting cell will carry the mutation and the resulting trait.

Are Mutations Good or Bad?

A mutation in the DNA may have no effect.

• However, sometimes a mutation can cause a protein to be made incorrectly.
• A defect in the protein can affect how well the protein works, or whether it works at all.

Sometimes the resulting trait does not help or harm the organism, it is neutral.

• For example, heterochromia is a mutation that causes two different colored eyes.
• Having two different colored eyes does not help or harm the organism’s chance of survival so it would be considered a neutral mutation.

Usually the loss of a protein function is detrimental to the organism and makes it harder to survive.

• This rare albino alligator has the mutation for albinism.
• Albinism is a mutation in a gene for melanin, a protein found in skin and eyes.
• Such a mutation may result in no melanin production at all or a significant decline in the amount of melanin.
• The resulting color will make it harder for the alligator to camouflage with its surroundings.
• This mutation has a negative impact on the alligator's chance for survival.

This rabbit also has the mutation for albinism.

• If this population of rabbits lives in a dark forest this mutation would be harmful.
• However, would this mutation be harmful if the population of rabbits lived in the snowy arctic?
• In rare circumstances a mutation can help an organism survive in their environment.
• For example, humans have the ability to see more colors than other animals.
• This ability is the result of a mutation that occurred a long time ago.
• Organisms that have those beneficial mutations are more likely to survive and pass the mutation to future generations.

Causes of Mutations

Some mutations are not caused by errors in DNA replication.

• Mutations can happen spontaneously, and they can be caused by mutagens in the environment.
• Some chemicals, such as those found in tobacco smoke, can be mutagens.
• Sometimes mutagens can also cause cancer.
• Tobacco smoke, for example, is often linked to lung cancer.