Discussion

Point mutations are errors that occur in a single place on a gene. Because these mistakes change just one tiny piece of information in one single piece of DNA, they usually do not cause any problems. Imagine if someone sent you a long e-mail and accidentally misspelled the word "friend" as "fmiend." You would still understand the e-mail and would probably still even catch the original meaning - this is a good analogy for what happens with a point mutation. 
Sometimes, in very rare cases, a single mistake can make a big difference. Imagine if, in another long e-mail, you were told that your life depended on how much "money" you could collect. But a spelling error changed that key word to "honey." You can imagine how such a mistake might cause great confusion and a possibly awful (and very sticky) outcome. Just one letter was mutated, but the whole meaning of the warning e-mail was altered. 
Similarly, Cystic Fybrosis (CF) is often caused by a point mutation of one single letter of one small stretch of DNA. This tiny error makes a massive difference in the way a person with CF lives. Begin this week's discussion by going through the National Institutes of Health's multimedia tutorial (with audio) here: 
http://www.nlm.nih.gov/medlineplus/tutorials/cysticfibrosis/htm/ lesson.htm 
You may also want to use the National Heart Lung and Blood Institute's CF site: 
http://www.nhlbi.nih.gov/health/dci/Diseases/cf/cf_what.html 
Discussion Topic(s): 
Point mutations 
During the week, you should address the following issues in your discussions - please do not lump responses to all these questions into a single post, however. Your goal is to address many of these issues in several posts throughout the week

DB 1 of 5 - CF is pretty scary 	
Edward Jackson 	
3/3/2012 5:37:18 PM	

	
If both parents must have a point mutation in their CF genes in order to create a child with CF, how common do you think the disease is in the population? Explain.
After watching the video training, I learned that even though there are only roughly 30,000 people who have CF, there are 12 million carriers.  This means that if 2 parents are carriers, there is a 1/4 chance that their child will acquire the gene deficiency.  Quite scary when you think about it.  I did find the video highly informative, and learned a lot about CF.  There is also the chance that even if both parent are carriers (Gg), that they could pass the genetic structure of GG to their child.  GG is a non-carrier and does not have the genetic disorder.  One sad thing I did learn is that a person with CF has a very short life span of around 30 years.  The build-up of thick, heavy mucus is what causes most of the symptoms.
Reference:
Medline Plus (1995-2012).  Cystic Fibrosis.  Retrieved on 03/03/2012, from http://www.nlm.nih.gov/medlineplus/tutorials/cysticfibrosis/htm/_no_50_no_0.htm.

------------------------------------------------------
Eddie Jackson
GOK - Philosophy Major/Liberal Studies
http://eddiejackson.net  university page

Mucus builds up

	

DB 2 of 5 - Mutations 	
Edward Jackson 	
3/3/2012 5:56:07 PM	

	
Why do you think another mistake doesn't just "correct" the mutation in an abnormal CF gene? 
What do you think the chances of this occurring would be? Compare this likelihood to the chance
 of some other event happening.

Mutations tend to be one way, meaning that once a mutation has occurred, that it is highly 
unlikely that another mutation would simply "fix" the genetic defect.  I like to think of science 
one day being able to reverse, or even better, prevent genetic defects.  But because our 
understanding of genes and what they do are still in its infancy, it's quite a slippery slope. 
Tampering with a gene could have serious implications on the very existence of humans.  
Something that comes to mind, is a future where no diseases exist because we have eradicated
them through genetics.  But then all humans become sterile for no reason, with no solution to
repair what we have done.  Wouldn't that be a predicament?

------------------------------------------------------
Eddie Jackson
GOK - Philosophy Major/Liberal Studies
http://eddiejackson.net  university page

http://www.cancer.gov/PublishedContent/Images/images/documents/2bb8687b-eb2b-4e62-ba30-a0572dee414e/cancer10.jpg	

 

DB 3 of 5 - other diseases 	
Edward Jackson 	
3/3/2012 6:40:47 PM	

	
What other diseases are thought to be caused by point mutations? What do point mutations do in those diseases? 

One common disease that is caused through point mutations is Sickle Cell. 
This point mutation causes the hemoglobin in red bloods to become distorted when being deoxygenated, into the form of a sickle, thus the name. 

Reference: 
The Tech Museum (n.d.). When Genes Go Bad: Mutations and Disease. Retrieved on 03/03/2012, from http://www.thetech.org/genetics/art04_bad.php 

http://images.medicinenet.com/images/illustrations/sickl_cell.jpg

Another point mutation is color blindness.  This is caused by a photoreceptor disorder and the person has problems determining the difference between reds, yellows, and greens.

Reference:
ECONOMICexpert.com (n.d.). Color Blindness.  Retrieved on 03/03/2012, from
http://www.economicexpert.com/a/Color:blindness.htm

Can you see the numbers?

http://gene-test.org/images/colorblindness.jpg

------------------------------------------------------
Eddie Jackson
GOK - Philosophy Major/Liberal Studies
http://eddiejackson.net  university page	

DB 4 of 5 - Advice 	
Edward Jackson 	
3/4/2012 4:08:49 PM	

	
First my first advice would be to have the child see a nutritionist, because diet really does matter.  There is extra salt loss through the skin, so the child could definitely suffer from a sodium deficiency.  A high calorie, high fat diet is usually the norm for a child who has CF, and a nutritionist would know exactly what kind of diet the child would need. My second advice would be to make sure the child is on a regular exercise routine, as a strong body can better fight off bacteria and lung infections.

On a personal note, I would offer my time for doctor visits or to watch the child, to give the parents a break.

Reference:
Cystic Fibrosis (n.d.). Staying Healthy.  Retrieved on 03/04/2012, from
http://www.cff.org/LivingWithCF/StayingHealthy/.

------------------------------------------------------
Eddie Jackson
GOK - Philosophy Major/Liberal Studies
http://eddiejackson.net  university page

	

DB 5 of 5 - Pregnancy 	
Edward Jackson 	
3/4/2012 9:19:59 PM	

	
It would be extremely risky for a pregnant woman to be exposed to mutagens because the mutagens can cause birth defects in the fetus.  A fetus being exposed to mutagens like the chemicals in cigarette smoke, certain medications and alcohol, could be born with possible problems with their lungs, sight, size, cancer and could even result in death.  As far as safe exposure, no exposure or as little as possible, is the safest approach.  I say this because every person's body is different, it's hard to say what the individual's tolerance level is to any given mutagen.  I say don't take chances.

Reference:
Most Gene (1995). Teratogen Update Mutagens.  Retrieved on 03/04/2012, from
http://www.mostgene.org/gd/gdvol12f.htm

------------------------------------------------------
Eddie Jackson
GOK - Philosophy Major/Liberal Studies
http://eddiejackson.net  university page

http://farm1.static.flickr.com/193/464314427_194c515f33_o.jpg 

	

RE: Initial Response to Q1 (1&2) 	
Edward Jackson 	
3/5/2012 1:08:22 PM	

	
I totally agree with you that there are too many outcomes with genes.  It seems quite impossible that one genetic defect or mutation would cure or fix another defect.  I think we still have a long way to go when it comes to understanding how all the genes are tied together to make up a person.  I dream of a future where scientists have figured out how to reduce birth defects, but I am also concerned that we may do more damage than good.

I say move forward with science, but we need to be very cautious, and keep any genetic alterations tightly controlled.

------------------------------------------------------
Eddie Jackson
GOK - Philosophy Major/Liberal Studies
http://eddiejackson.net  university page

	

RE: discussion question 1and 2 	
Edward Jackson 	
3/5/2012 1:22:49 PM	

	
I find it quite amazing that 12 million people are carriers.  Before this class, I did not know that.  Makes me wonder why people aren't getting screened for CF "before" they get pregnant.  Through medicine, we could eradicate this defect over time.  It would just require mass education and mandated testing before having a child.  As far as one mistake correcting another, it's possible in the realm of anomalies, but there is no way a person could depend upon that.  We are talking about the health of your child.  I'm all for keeping expecting mothers away from mutagens, reducing the chances of preventable birth defects.

------------------------------------------------------
Eddie Jackson
GOK - Philosophy Major/Liberal Studies
http://eddiejackson.net  university page

http://www.dr.marahimi.com/wp-content/uploads/2012/02/cystic_fibrosis03-2.jpg