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Chromosomal Mutations

Gene mutations can occur spontaneously or could be induced by exposure to chemicals or radiations. Mutations are of various types, ranging from point mutations to expanding repeats. Each mutation is classified by the way it alters the DNA.

Types of Mutation
A sentence made of three-letter words can provide an analogy to the effect of mutations on a gene's DNA sequence.
Normal THE ONE BIG FLY HAD ONE RED EYE
Missense THQ ONE BIG FLY HAD ONE RED EYE
Nonsense THE ONE BIG
Frameshift THE ONE QBI GFL YHA DON ERE DEY
Deletion THE ONE BIG HAD ONE RED EYE
Insertion THE ONE BIG WET FLY HAD ONE RED EYE
Duplication THE ONE BIG FLY FLY HAD ONE RED EYE
Expanding mutation
Generation 1 THE ONE BIG FLY HAD ONE RED EYE
Generation 2 THE ONE BIG FLY FLYFLY HAD ONE RED EYE
Generation 3 THE ONE BIG FLY FLYFLYFLYFLY HAD ONE RED EYE

Complete the following discussions:

Describe a genetic disorder resulting from one of the mutations listed in the table. What is the mode of inheritance of your chosen disorder? What does the affected gene sequence look like in comparison to the normal sequence? What is the change in the amino acid sequence as a result of the disorder?

Describe the DNA repair process in eukaryotes. Why do you think this process is absent in mitochondrial DNA? What properties of mitochondrial DNA prevent it from repairing itself?

Which genetic disorder results from this karyotype? Describe two purposes of performing a karyotype (other than detecting abnormal chromosome numbers). In your opinion, should karyotyping be performed in the early stages of pregnancy to look for genetic disorders? Why or why not?

Identify two types of chromosomal abnormalities that can result from addition, deletion, or duplication of genetic material and describe how it happens. Describe a genetic disorder that can result from one of the aberrations identified by you.

Solution Preview

One genetic disorder that I believe fits all of the mutation types is Nephrogenic Diabetes Insipidus. It is a rare disease that is most commonly X-chromosome linked (roughly 90% of cases). There are over 100 known mutations that cause this disease. The mutations occur to the AVPR receptor in the nephron of the kidney. The receptor takes in the hormone vasopressin (anti-diuretic hormone or ADH) which tells the kidneys to retain water (ADH is released in response to heat stress). The mutation(s) range from minor structural ...

Solution Summary

This solutions discusses some examples of mutations that can occur in nuclear and mitochondrial DNA. Brief discussion and examples are given.

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