As I am sure many of you already know, there was a new bacteria, strain GFAJ-1, discovered by NASA scientists in Lake Mono in California that is able to use Arsenic as a building block in the place of phosphorus. I found a nice simple to read article explaining the details of this discovery on NASA's website entitled NASA-Funded Research Discovers Life Built With Toxic Chemical . The bacteria were found in Lake Mono which has very high salinity, alkalinity, and levels of arsenic. Arsenic is poisonous to all known forms of life on earth because its similar structure and chemical behavior to phosphorus cause it to interfere with metabolic pathways. However, this new bacteria is able to work in place of phosphorus when phosphorus is in short supply or is absent all together. This discovery will expand the current definition of life and will open up new doors of research in the field of microbiology. Although the implications of this finding are not extraordinarily dramatic, it is interesting to wonder about other ways that life is able to function that we haven't considered yet.
This week I read an article about Marsupials and the curiousness of their limb development. I found this reading on ScienceDaily's website and is entitled Marsupial Embryo Jumps Ahead in Development . The researchers at Duke University claim that the "developmental program executed by the marsupial embryo runs in a different order than the program executed by virtually every other vertebrate animal". This, although interesting, is already widely known. The interesting part of the article is when they talk about how they are developmentally different. The researchers studied the limbs of the embryonic short-tailed opossum. They found that not only is limb development occurring at a different order of typical vertebrate development, but also that the development of the limbs is occurring before almost any other structure. Previously limb development has been thought to be triggered by the development of other structures in the body but at least in the case of the short-tailed opossum limb development is occurring without these triggers. It is suspected that these results will hold true for many if not all other marsupials as well. This doesn't even correlate to all of the limbs; the forelimbs are what mainly develop early because they are used to drag themselves across their mother in search of her teat in order to feed. While the forelimbs contain developed muscle and bone, the hind-limbs still are rubber like and weak. It is amazing that such an underdeveloped animal can actually survive living outside the mothers womb at such an early age. Though the baby may have a harder time surviving, marsupial mothers in general have an easier time surviving because if resources become scarce or they need to evade a predator, they can easily give up their baby to save them selves and reproduce later. Overall I think that this article was very interesting because the results suggest that development is much more flexible than we have previously thought.
This article entitled Sea Creatures' Sex Protein Provides New Insight Into Diabetes suggests that genes in sea urchins can explain why a rare form of diabetes called Diabetes Insipidus occurs. Diabetes Insipidus causes a person to urinate more than three liters a day. People with this disease lack the ability to produce vasopressin which tells the body how much urine to make. Professor Maurice Elphick, from Queen Mary's School of Biological and Chemical Sciences, says that sea urchins produce NG peptides (responsible for releasing their sperm and eggs at the same time) very similarly to how humans produce this vasopressin. He believes that we can trace our genetic history back to a common ancestor between sea urchins and humans where a one-off genetic accident when a gene that was responsible for making vasopressin-like molecules mutated and became a gene for NG peptides. Research on how sea urchins produce NG peptides can reveal how humans produce vasopressin. This could lead to ways in which Diabetes Insipidus could be cured or prevented.
I stumbled upon an interesting video/article on Science dailys website entitled Doggy Genes Newly Sequenced Genome Could Shed Light on Human Diseases. Researchers have completed the first complete genetic map of a Boxer's (dog breed) genome. Researchers are hoping that not only will this lead to a better ability to treat diseases in dogs, but also help treat and find cures for diseases in humans. Dogs and humans share many diseases such as diabetes, epilepsy, and cancer If they can identify the genes that cause these diseases in dogs they may be able to find a cure. If they can find a cure that works on dogs then it would be likely that it could cure the diseases in humans due to the similarities between our genomes. Dogs make an excellent genome to search for genes for common diseases with humans because a disease that is caused by a dozen genes in a human is only caused by one gene in dogs. This makes things a lot easier to identify and study. Implications of this research are that there are many different breeds of dogs many of which have higher predispositions for certain diseases. Currently they have only mapped out the genes of one breed of dogs, boxers, it would be helpful for them to map out the other breeds of dogs and look for specific genes in specific breeds.
This week I read a very interesting article on the science daily website entitled Modeling Autism in a Lab Dish: Researchers Create Autistic Neuron Model . Autism has previously been viewed as a learned disorder thats caused by bad parenting skills however it has been found that in almost all cases of autism it is caused by a mutation in the MeCP2 gene. The researchers used iPS skin cells from autistic participants. The skin cells were then "encouraged" to have the same mutations and damages as autism. They then created fully functional neurons from the cells at which point the researchers compared the cells of autistic participants to those in the control group. They found that the autistic cells had smaller cell bodies, a reduced number of synapses and dendritic spines, specialized structures that enable cell-cell communication, and electrophysical defects. However, when they added insulin-like growth factor 1 (IGF-1) to the cells, the differences decreased. Their research suggests that in the future it is possible to cure autism to some extent. This research could also be used to treat and cure other psychiatric disorders as well. If implemented, this research could improve the lives of millions of people with psychiatric disorders.
To read more, the original article was published in the November 12, 2010 issue of Cell.
This week I read a very interesting article entitled Gene mapping project offers new clues about humanswritten by Julie Steenhuysen. In this article the researchers are trying create a map of genetic varients in humans. They believe that this information will allow us to better understand the genetic basis' of human diseases for both common and rare diseases. Dr. Evan Eichler of the University of Washington is in the process of mapping out 2,500 people's genomes from around the world. Although it is difficult to compare these genomes, it will hopefully give us an idea of why certain people have certain diseases. I think this research is very important because if we can identify the genes that lead to certain diseases then it would be possible to treat the person earlier giving them a higher rate of recovery. I think it would be interesting to follow up on this research and see where it leads us in the future.
I thought this article entitled Why the Leopard Got Its Spots was interesting because it closely related to our reading assignment for our classroom discussion this week; Chapter 9 "Paint it Black" in Sean B. Carroll's "Endless Forms Most Beautiful. The researchers also used mathematical modeling to formulate their results which was the topic of my essay test last week. Because of these coincidences, this article seemed fitting. The article explains that the cats that live in low light habitats due to canopy coverage are more likely to be spotted. This makes sense because the light is coming through the canopy in splotchy patterns similar to that of a spotted leopard. The same concept is explained in further detail in our readings by Sean B. Carroll, but even he quotes Rudyard Kipling's "How the zebra got its spots". The article explains that it is expected that in "closed" environments (lots of trees, less sunlight penetration) we would observe spotted cats whereas in "open" environments (such as a savannah grassland) we would see a solid coat pattern. However there are some exceptions to this. But there are exceptions to this, why? The answers to these exceptions are not explained in this article. In the case of the cheetah, could the lack of genetic diversity play a role in the retention of spots despite an open environment?
This week, while procrastinating with my homework and spending time on facebook I stumbled upon a link to a very interesting article. This article entitled A Solar Salamander. from nature news suggests that photosynthetic alga was found inside the cells of spotted salamander embryos. This alga (Oophila amblystomatis) was previously thought to have only a symbiotic relationship with the salamander embryos. The salamanders benefit from the increased oxygen content surrounding them that the alga releases and the alga benefiting from the nitrogen rich wastes that the embryo releases. It is thought that the alga might get into the salamander while they are expelling wastes. However, this alga has also been found in the cells of the reproductive organs of female salamanders suggesting that they might pass the alga onto their embryos through their eggs. Other close relationships between invertebrates and photosynthetic organisms have been seen before, but never in vertebrates. It is hypothesized that if researchers start looking for other examples like the spotted salamander, they will find many more examples.
This week I read the press release of The Nobel Prize in Physiology or Medicine 2010: Robert G. Edwards. Robert G. Edwards won the award for his research and development of in vitro fertilization. He first envisioned in vitro fertilization and its useful applications in the 1950's but it wasn't until July 25th 1978 that the first successful birth of an in vitro fertilized baby was born. Though there has been controversy over the ethics of this method of fertilization, in vitro fertilization has produced over 4 million births of healthy babies since Louise Brown, the first test tube baby. The article states that about 10% of couples worldwide experience infertility issues. I think this is why Edwards was an excellent candidate to win this Nobel peace prize; because his work does not only contribute to the scientific community but also helps millions of families overcome their infertility issues. His work directly affects the lives of everyday people, not just people who follow scientific findings.
This week I read a really interesting article about ADHD called "First Direct Evidence That ADHD Is a Genetic Disorder: Children With ADHD More Likely to Have Missing or Duplicated Segments of DNA" . The article was about the researchers identifying a gene that could be linked to ADHD. This is different than what is previously thought; that ADHD was caused by poor parenting skills or poor diet. The researchers tested 1,000 unaffected children and 336 children affected by ADHD and compared their genomes. They found that children who had been diagnosed with ADHD have significantly higher rates of duplicated or missing sequences of DNA. Also, it has been identified that the parts of the DNA that have been affected are also the parts that influence susceptibility to Autism and Schizophrenia. It is thought that ADHD is not caused by just one genetic change but by many genetic changes and how they interact with the person's environment. The researchers do not think that genetic testing would be a good way to diagnose children. They think the clinical assessment already in place to test for ADHD is good enough. However, this research is important because it provides new information about the disease and also helps to remove the stigma of ADHD being cause by poor diet and poor parenting skills.