Sunday, March 17, 2013
PROMPT 2: Genetics of Aging
On pages 184-185, Dr. Moalem discusses a devastating disease called progeria. This disease is characterized by accelerated aging where patients start experiencing wrinkling, hair loss, arthritis, and other degenerative diseases by the age of one and a half, which ultimately leads to premature death. Scientists in 2003 discovered the gene mutation that causes progeria. Big Idea 3: Living systems store, retrieve, transmit, and respond to information essential to life processes can be applied to this concept, because this issue discusses gene expression, and how DNA/possible mutations in the DNA affect cellular activities.
What is the name of the affected gene? What are the effects of the gene mutation that cause progeria? Think along the lines of gene expression and protein synthesis when answering this question. What does the discovery of this gene show about aging?
Describe the Hayflick effect and the role of telomeres. (Hint: There's a clever analogy on pg. 186!) How does telomerase alter the Hayflick effect and telomeres?
How are the life expectancies of a species and the external threats the species undergo related?
Mutations on the lamin A gene (aka LMNA) that cause progeria can lead to a wide variety of other diseases as well. Research another disease/disorder that results from LMNA mutations. Discuss what time of mutation(s) occured, how it affects the patient, and the symptoms of the disease.
(Michelle Liang, mliang4@students.d125.org)
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Since DNA codes for all of the proteins in a cell, if there is a mutation in the DNA, then protein, translated from the RNA, will lose its function. The cell then produces useless proteins which cause the cell to not perform the right cellular activities. Progeria is caused by a defect on gene LMNA (Source 1). The mutation causes a deficiency in lamin A, a protein that provides structural support to cells (pg 184). There is a mutation in the sequence of the gene LMNA, this causes the protein lamin A to be useless to the cell and not be able to perform its proper function by providing support to the cell membranes. This shows scientists that aging happens on a genetic level, and shows that aging may have been evolutionary significant. The Hayflick effect is when there is a limit on how many times a cell can divide (pg 185). Telomeres are the buffer on the ends of DNA which provide protection to the DNA every time the DNA replicates. Once the Telomeres are gone the DNA can no longer replicate and the cell cannot divide, thus the Hayflick effect comes into place. Telomerase extends the telomeres at the ends of the DNA making the DNA able to replicate more and thus the cell divides more. The Hayflick limit is slowed down. Another disease caused by a mutation on LMNA is Emery-Dreifuss muscular dystrophy. The disease is usually present at the age of 10. The patient suffers from weakness in the muscles and tendons, and cardiac defects. This restricts the patient from being able to perform everyday actions such as walking or reaching for objects. The disease also restricts the patient from physical exercise since cardiac problems are usually found (Source 2).
ReplyDelete1) Dale K. Shumaker, Thomas Dechat, Alexander Kohlmaier, Stephen A. Adam, Matthew R. Bozovsky, Michael R. Erdos, Maria Eriksson, Anne E. Goldman, Satya Khuon, Francis S. Collins, Thomas Jenuwein and Robert D. Goldman Proceedings of the National Academy of Sciences of the United States of America , Vol. 103, No. 23 (Jun. 6, 2006), pp. 8703-8708
2) "Emery-Dreifuss Muscular Dystrophy." European Journal of Human Genetics 10.3 (2002): 157-61. Print.
Anna Podber (apodber3@students.d125.org)