Genetic Inheritance and Mutation

Mutations are changes that occur within the genes of an organism. Sometimes these mutations impact a single gene, while other mutations impact the number or structure of entire chromosomes. Since many mutations change just one tiny piece of information in one single piece of DNA, they usually do not cause any problems. For example, imagine if someone sent you a long email and accidentally misspelled the word “friend” as “freind.” You would still understand the email and would probably still even catch the original meaning – this is a good analogy for what happens with a point mutation, where just one part of a gene is changed.

However, sometimes a single mistake can make a big difference. Imagine if, while composing a long email, you accidentally select and delete an entire paragraph or perhaps auto-correct changes a critical word. You can imagine (and perhaps have even experienced) how such a mistake might cause great confusion and miscommunication.

Many genetic disorders are caused by changes to a single gene in the form of a point mutation or due to a chromosomal abnormality like a chromosome disorder. Sometimes these mutations are passed from one generation to the next, just like other harmless traits like eye color and blood type. These mutations may cause specific disorders, or they may predispose a person to a common disease like cancer or heart disease.

Review the Discussion resources to learn more about genetics and the implications of our genetic knowledge:

During the week, discuss the following with your classmates. Be sure to use the provided course materials and feel free to share additional information you find in the PG Library or through your own research.

Imagine that you have a particular genetic trait and that you have four children. Two of the four children also possess this trait. Meanwhile, the other biological parent of your children does not possess the trait.

• Explain why you think the trait in the scenario is dominant or recessive.
• Based upon your response, describe why it would or would not be possible for the trait in the scenario to “skip” a generation.
• Patterns of inheritance within organisms like pea plants, fruit flies, mice, and others are somewhat easy to determine since their mating practices can easily be controlled. Apart from controlling who mates with whom, what other characteristics make species like these ideal for studying genetics?
• Select and describe a health problem that you believe has a genetic component at least partially inherited. If you do not identify an inherited health condition within your family, choose a disease that interests you or impacts a friend or other family member.
• Would you be interested in having genetic testing to determine whether you carry a genetic mutation for a particular disorder or a genetic predisposition for a disease? Why/why not? What are the advantages and disadvantages of determining your predisposition?
• Explore the current state of research for the health problem you selected. Focus on one of the following to discuss as they relate to the genetics of the disease:
  • Cause
  • Testing/Screening/Prevention
  • Treatments/Therapies/Cures