Tuesday, December 8, 2009

DNA Mutations/Insertion Mutation/Myotonic Dystrophy

There are several types of DNA Mutations that can occur. These range in many different categories such as Substitution, Insertion, Deletion, and Frameshift. I chose to research DNA Insertion more in depth. This form of mutation occurs when one or more nucleotides are inserted into a sequence. If a number of inserted bases are not a multiple of 3, it will cause a frameshift resulting in serious consequences. Non-frameshifting insertions however may cause diseases. One disease that I chose to research further was Myotonic Dystrophy. This disease is a result of Non-frameshifting instertions. Myotonic Dystrophy is a chronic, slowly progressing, highly variable inherited multisystemic disease. This disease causes the weakening of muscles, heart conduction defects, and endocrine changes. This disease is categorized into two different disease types. Type 1 and type 2, type 1 being more severe and type 2 being mild to moderate. Type 1 occurs in nearly 98% of the cases of Myotonic Dystrohpy while type 2 makes up the remaining 2%. Some symptoms that occur with this disease are severe muscle pain, muscle fatigue, and delayed learning in regards to language and behavior. This disease also causes people to become insulin resistant, meaning there isn’t an adequate amount of insulin in the body. Other symptoms that are present in this disease can occur at birth. Type 2 or the milder version of Myotonic Dystrophy has been found to be present during many births causing congenital defects to developing fetuses. This symptom has yet to be found in Type 1 Myotonic Dystrophy. Myotonic dystrophy is a genetic condition which is inherited in an autosomal dominant pattern and thus will be passed along to 50% of a carrier's offspring, on average. There are currently no known treatments for Myotonic Disorder due to the plethora of symptoms.

1. Explain another type of DNA Mutation.
2. What is another disease caused by DNA Insertion and explain it.
3. When a disease is autosomal dominant what doe this mean?

3 comments:

  1. 1. Deletion is when a segment of DNA is lost. For example, if a segment is TAGGCA if it was mutated by deletion it would be TCA. This would clearly cause some issues.
    2.Huntington's Disease. It is caused by the repetition of CAG sequence. It is normally repeated 9-35 times. A mutated gene will repeat 37-100 times. Huntington's causes uncontrolled movements, loss of mental facilities, and emotional disturbance.
    3.Where an individual has a copy of a mutant gene and a copy of a normal gene. These individuals have a 50/50 chance of passing on the mutated gene.

    ReplyDelete
  2. 1. Point mutation is a simple change in one base of the gene sequence.

    2. Sickle cell disease is an inherited disease caused by a genetic mutation. Genes are found on structures in the cells of our body called chromosomes. There are normally 46 total, or 23 pairs, of chromosomes in each cell of our body. The 11th pair of chromosomes contains a gene responsible for normal hemoglobin production.

    3. An individual has a copy of a mutant gene and a copy of a normal gene.

    ReplyDelete
  3. 1.Frameshift mutation changes the amino acid sequence from the site of the mutation.
    2.Kennedy's disease. Also known as spinal bulbar muscular atrophy, or SBMA. Its and inherited neuorlogical disorder. Its caused by a genetic defect on the X chromosome. SInce males have X chromosome they are more affected by this disease.
    3.it is one of several ways that a trait or disorder may be passed down trhough families.

    ReplyDelete