Scientists have recently identified a section of “junk” DNA that can regain function and cause disease.  The section of DNA is made of repeat regions of the same sequence.  They found that individuals who have 1-10 repeats on the end of chromosome 4 can develop one of the most common forms of muscular dystrophy, FSHD.  The goal now is to identify a way to turn off this once non-functioning gene.    

 One of the important insights from the resurrection of this gene is that although some diseases can be easily explained, others result from very complicated cellular interactions.  What other information will our “junk”DNA reveal in the future? 

To learn more about the effects of this gene being turned on read the paper published in Science:  http://www.sciencemag.org/cgi/rapidpdf/science.1189044.pdf

HIV (in green) budding from an infected white blood cell

We are in the midst of a media explosion surrounding the possibility of a vaccine for HIV.    For years this has seemed a hopeless situation, so a great deal of effort and money has been spent on the campaign to educate people about transmission and prevent infection.  Unfortunately, according to recent reports (http://www.mg.co.za/article/2010-07-12-hiv-vaccine-the-only-real-answer), the number of new infections is still an alarming 7400 per day!  In addition, less than half of the 9.5 million people in low-middle income households infected with HIV have access to anti viral treatments. 

These staggering statistics demonstrate very clearly that efforts to help infected individuals are available and do reach millions, but they just aren’t enough.  Development of a vaccine, probably the best method of prevention, has been an extremely slow process.  Students ask about this all the time.  If scientists can eradicate small pox, if they can make a new flu-shot every year, then why can’t they make a vaccine for HIV? The virus mutates so quickly that once infected, the host harbors any number of viral variants, all unique!

 Interestingly enough, one in four patients infected with HIV  carry two very strong anti-HIV antibodies that seem to neutralize 91% of  HIV strains (http://www.webmd.com/hiv-aids/news/20100709/antibodies-discovery-may-pave-way-to-aids-vaccine )  .  Why don’t they work?  They usually aren’t produced until the infection is rampant, and by the time they are produced, the virus has begun to mutate!  So, the thought process is this:  if individuals were given a vaccine that elicited the production of these antibodies before exposure to the virus, they would likely prevent infection upon exposure.  The key now is development of the vaccine, and then dissemination to regions in need.  

The identification and isolation of these antibodies have shed some light on what seemed to be an almost hopeless situation. I look forward to the next five years of research in this field and believe that there will be a vaccine in the next 10.

Neandertals, the extinct species of what are most likely our closest relatives, lived on earth at the same time as our human ancestors but died out about 30,000 years ago. With the sequence of their genome now complete, we can compare the DNA to humans and chimpanzees to learn more about what makes humans unique as a species.

The discovery of fossils is an exciting link to our past. Although the fossil bones do contain DNA, much of it is contaminated. Dr. Emily Hodges at the Cold Spring Harbor Laboratory developed a technique to quickly identify and amplify specific portions of contaminated DNA accurately. Referred to by her team as ‘array capture re-sequencing’, the procedure uses regions of human exons (lengths of DNA that code for proteins) to probe for (or fish out) the Neandertal exons from contaminated DNA samples.

Through the technique they were able to identify 88 differences (in a total of only 83 proteins) between human and Neandertal protein sequences. Amazing!

Go to the following links to access both papers:

The Draft Sequence of the Neandertal Genome:
http://www.sciencemag.org/cgi/reprint/328/5979/710.pdf

Targeted Investigation of the Neandertal Genome by Arrary-Based Sequence Capture:
http://www.sciencemag.org/cgi/reprint/328/5979/723.pdf

For addition information on Neandertals:

Science Magazine:
http://www.sciencemag.org/special/neandertal/feature/index.html

DNA Interactive:
http://www.dnai.org/ (under applications>human origins)

Interviews with Svante Paabo:

DNA From the Beginning:
http://www.dnaftb.org/30/concept/index.html (under audio/video)

One of the cooking tips that I have picked up from all of the foodie shows I watch is to use fresh herbs, whenever possible.  Believe it or not, that green spring of parsley on my plate at restaurants that used to repulse me, has actually become a part of my regular cooking repertoire.  Turkey meatloaf just wouldn’t be the same without it!  My homemade pizza now seems bland without fresh basil. 

The one herb that I just can’t get cozy with is Cilantro.   It turns out that I’m not the only one.  There are lots of people who also dislike the flavor of these green leaves, as well as their seeds (aka. Coriander).  The plant produces molecules called aldehydes, that determine its scent and taste.  It turns out that aldehydes are also found in soaps and lotions, hence the soapy taste that some report.   

It is known that genes play an important role in taste, but there isn’t sufficient data in this field to pinpoint specific genes or gene variants to explain the Cilantro phenomenon.  It is also known, that the evolution of taste and smell has played an important role in our survival.  It’s possible that the cilantrophobe’s distaste is a result of the choice some of our European ancestors made when they turned their noses up at the herb, hundreds of years ago.   

 In the article, “Cilantro Haters, It’s Not Your Fault” by Harold McGee of the New York Times (http://www.nytimes.com/2010/04/14/dining/14curious.html?partner=rss&emc=rss?)  cilantrophobia can be overcome, through association of the flavor with positive experiences.  Makes sense, but I’m not sure I’m even willing to try!

Scientists from the University of Geneva have shown that alpha cells in the pancreas of mice have changed to insulin producing beta cells. In the study, approximately 5 % of the alpha cells became beta cells. The response seen only occurs in mice when the majority of the beta cells have been eliminated. If scientists can find a way to encourage human cells to transform in a similar way while preventing the immune system from destroying the new cells, even a small percentage of new beta cells could make a huge difference in the life of a diabetic.

Identification of the mechanisms that transform alpha cells into beta cells will not only help in the treatment of diabetes but can reveal insights into the ability to direct changes in other cells, including cancer.

PDF of the Article In Nature:
http://www.nature.com/nature/journal/vaop/ncurrent/pdf/nature08894.pdf

Viruses come and go, but there are some that just seem to come back every year, like the adenovirus that causes the common cold.  Because it mutates so quickly, we’re infected by different adenoviruses each year.  Another common viral ailment is gastroenteritis, which can be caused by the astrovirus, norovirus or rotavirus.  Growing up, the “stomach flu” seemed to move through the members of our household annually.  When one person began to vomit, it was only a matter of time before the next victim fell, until everyone had been wiped out…..except my Dad.  He just never got the stomach flu! 

This unique, and very desirable trait in my opinion, is most likely due to a genetic variation in my father’s immune system. Interestingly enough, it is believed that viruses have played an important role in the evolution of an estimated 139 genes that control susceptibility to viral infections. These genes have been influenced over thousands of years by exposure to different viruses, in different geographic locations.  The selective pressure created through exposure has led to the accumulation of many genes that give their hosts “protection” from certain viruses.

Understanding how these genes and their protein products function is useful!  Is it possible that they might play an important role in the development of better treatments for specific viral infections, some kind of gene therapy to prevent viral infections like a “gene vaccine”, or maybe even cures! Although I always admired his ability to resist the stomach flu, I now see him in a new light.  He’s living proof that these genes exist, and that variety really is the spice of life!

To read more about viruses and human evolution go to:

http://www.sciencedaily.com/releases/2010/02/100218203053.htm

The recent sequencing of the panda genome has provided even greater insight into the significance of microorganisms. Panda’s have a mutation in the gene that enables them to taste food high in protein, including meat and cheese. Since they are unable to taste these foods, they eat bamboo as an alternative. Interestingly, panda’s do not contain the genes necessary to produce the enzymes to digest bamboo. So how do they get any nutrients? The small organisms living within their digestive system are responsible for releasing the nutrients from their diet. Amazing!

How much of our own health due we owe to the organisms within us?

For example, when someone has hemophilia (a blood clotting disorder), there is a mutation in a gene that normally tells our cells how to make proteins called clotting factors. The mutation prevents a specific clotting factor from being produced, and as a result, the individual carrying the mutation has the disease and the blood doesn’t clot as it should after an injury. It’s a gene we all have, but if someone has hemophilia, the gene just isn’t working properly.

Another common misunderstanding is that if a disease is genetic, it is always inherited. It is true that many disease-causing mutations are inherited. Sometimes though, the mutations that cause genetic diseases develop over time, after we are born. Many of the mutations associated with the development of cancer, accumulate in our cells as we age, and aren’t inherited. These diseases are genetic, because they are caused by mutations in genes, but they aren’t passed from parent to offspring. Less than 10% of all cancers are inherited!

It’s no wonder that not only children, but adults too, are misinformed. These types of incorrect phrases and misinterpretations are printed all the time in magazine and newspapers. So where do you go for correct information? To learn more about the genetics of cancer, go to: www.insidecancer.org. To learn more about basic laws of inheritance, use DNA From the Beginning (www.dnaftb.org). To learn more about the inheritance of mutations that cause disease, go to: http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gnd, the Online Mendelian Inheritance in Men (OMIM) database.

One example of controlled behaviors has stirred up a variety of questions. A species of fungus, Ophiocordyceps unilateralis, infects a type of carpenter ant. What is unusual about the infection is that the fungus somehow directs the ant to move to a location on the leaves of the trees normally inhabited by the ants. The location is highly specific in regard to temperature, humidity, and sunlight – ideal conditions for the fungus to grow.

Once the ant has been guided to the correct site, it is forced to bite down and lock its mandibles in place like an anchor. The ant quickly dies as the fungus takes over and uses the body to grow and produce spores. Any ants walking below are susceptible to the falling spores once they are released. You can check out the fantastic YouTube clip from FreeScienceLectures by clicking here.

How does the fungus control the ant? The scenario does bring up questions about why organisms have certain behaviors and what controls exist to direct them. What about our own behaviors is it predetermined by our genes?

A sea slug species, Elysia chlorotica, found in the marshes of New England and Canada has a unique trait. It produces chlorophyll and can use photosynthesis to make it’s own food – just like a plant! There are other organisms, not classified as plants, that have this trait as well such as the Euglena, a single-celled protist. This sea slug happens to be the first multicellular animal with such a trait. Scientists believe that they steal genes for this trait from the algae that they eat. They also steal chloroplasts, the organelle where photosynthesis takes place.

The stolen genes can be passed from one generation to the next, so that next generation sea slugs can also produce their own chlorophyll. Interestingly enough, the babies still need to eat lots of algae to get the chloroplasts they need to carry out photosynthesis. So maybe there is hope for green people after all?