Tuesday, July 24, 2012

Genetics 101: Questions and Answers (Hopefully)

There's a day for everything, and last April 20Th  was DNA'S day, in which there was an open chat with all the geneticists, microbiologists and people involved in the Human Genome Project. (mind you that their minimum level of education was a PhD.) They were answering questions for the everyday street walker like me, with no more prior knowledge of the cell division than a model of play-doh made in the fourth grade, and a biology class in middle school were I probably was doing more important things like writing a love letter to whoever was my crush at that time. Darn it!

I did jump in the chat with my list of questions, at least the ones that would get a shot at being answered on this side of heaven, I hope and pray that this post reaches someone walking a similar path, because at my times of Goggling myself to death I wish that there had been such a post when I was new to the whole thing. Without more ado, this were the questions and answers from the chat. Most of the questions were mine, but some others were from other fellow chatters, and I though that they were worth the copy-pasting. Unfortunately, I cannot give the credit were is due, since some questions were anonymous, please understand. 

1. When a baby is born with a genetic syndrome, is there anything that one of the parents could have done different to prevent that? 
No, when a baby is born with a genetic syndrome there is not anything a parent could have done differently. 

Answer by: Kelly Donahue. Prenatal genetic counselor. I speak with families that are at risk to have children with genetic conditions. This risk may be based on their family history or be signaled by results of specific blood work or ultrasound during their pregnancy.

2. What are three things that every human should understand about DNA?
In my opinion: 1) DNA is the "blueprint" necessary for life 2) it transmits hereditary information from generation to generation 3) it controls the production of proteins.

Answer by: Sandy Woo: I work with patients and their families who either have a genetic condition or birth defect, are at risk for one or have a risk to have a child with such. I provide education, facilitate genetic testing decisions and psycho-social support.

3. What can DNA tell us about a person? 

That's a good question. Something like 99.9% of our DNA is the same no matter the person. The remaining DNA that's different makes us who we are compared to any other person. 

We also have mutations which alter the protein products of any given gene, and these are what we spend a lot of time and money researching. That's because many diseases either have a single gene mutation that causes them or different mutations that predispose one to certain diseases.

 A genome is the totality of all of our DNA spread over our 46 chromosomes. In the past, if we looked at an entire genome we wouldn't be able to tell much about the person. But now we're getting to the point scientifically that we can analyze an entire person's genome for a relatively low cost and in a shorter period of time. It won't be long that it will be very cheap to scan an entire genome to know every disease risk someone has, but we're not there quite yet. This is where most of science is focused, but note that DNA doesn't tell us many important things about a person, such as their character, values, or insights on life. Those traits are all influenced by genes, but are something DNA analysis will never be able to completely tell us.

Answer by: Ian Wallace: I am a clinical genetic counselor who recently launched a new genetics clinic in a rural area. I see patients for any genetic indication, to include prenatal, pediatric, adult, cancer referrals.
 
4. What are all the things that happen when the cell divides? 

Cell division is a complicated process. Let's think about mitosis, which is where one cell basically replicates itself, so you end up with two identical cells. 

What needs to happen is all of the structures of that starting cell needs to be copied. For example, all of the chromosomes need to be doubled and then halved into each ultimate cell. 

If you remember the process of mitosis, that's where the cell goes through prophase, metaphase, anaphase, and then telophase. The chromosomes become solid, they line up in the middle of the cell in an orderly fashion, and then structures on each end of the cell "pull" the right number of chromosomes to each new cell. And that doesn't even address what happens with the other cell organelles!

Answer by: Angela Filose: I work as a full-time genetic counselor for a Kaiser hospital, working with prenatal, pediatric, and hereditary cancer patients.
 
5. If a "mistake" were to happen, what happens to the DNA that was copied wrong? 

When DNA is being copied, there are different possible outcomes if there is a mistake. The cell actually has a few "proofreading" mechanisms to help fix some errors. For example, there is a group of proteins called "mismatch repair" enzymes, which helps to correct an error where the wrong base pairs are put together (like a G to a T, rather than a G to a C). So in some cases, the cell can correct the error.

Other times, an error like a deletion, a duplication, or a point mutation within a stretch of DNA might happen, and this could be missed. This might be an example where a permanent mutation could then continue with that gene, and possibly could change the function of that gene. 

Answer by: Angela Filose.

More Q&A to come, 




Image from : http://meship.com/Blog/2011/07/27/dna-sent-to-the-cloud/



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