Genetic Diversity and Killer Whale Population

       Genetic diversity refers to amount of gene characteristics found in the DNA of a certain species, and it is extremely important to the well being of that species. Genetic diversity and biodiversity are dependent on each other, and a healthy collection of genes is good for a species and their future offspring. This healthy collection of genes, those active and not are what best prepare an organism for survival in its environment, for example the difference in environment prompted a change in the squirrel's genome so that one select species evolved a patagium,  which is specialized membrane that stretches between the wrist and ankles. A normal squirrel would not adapt to its counter part's environment, as its disadvantage leaves it susceptible to predators, be it birds from above or snakes in the trees. Low genetic diversity can be detrimental to a population, in-adaptability to the environment can decimate it, the lack of variation in genes can leave them vulnerable to disease, eradicating the species. Low genetic diversity can be intentional or unintentional, intentional cases are usually those of agriculture, where as an unintentional case of low genetic diversity can be the result of natural disaster, this causes a bottleneck effect.

      A case of low biodiversity was recently revealed by researchers at Durham University, who concentrated their studies on the killer whale, and their ever falling number in population from the last Ice Age. The decline in diversity began about 40,000 years ago when many parts of this world were covered in ice, but for the killer whales, the richest currents, where there still were currents anyways, was the best place to reside. However, a number of killer whale pod, off the Californian coast, Humboldt off South America, and the Canary Islands  were not fortunate enough to find themselves in those rich current. This created a bottleneck effect among the killer whales, with only a pod off the coast of South Africa maintaining its genetic diversity. Even during a tumultuous time such as 40,000 years ago, great genetic diversity means a greater population, therefore we cannot sum up a population decline to shortage of food, or the inefficient hunting of early man. For a species to be so well spread out about the world, essentially as well globally distributed as humans, their genetic diversity should be much greater.

      The concern here is that similar to that period, a time when the environment was changing around the organisms inhabiting it, today we face the same issue. The world is changing around us, research has backed that, and we need to be proactive in a fight to maintain all that we have on the early today, to minimize the decline in population, because each organism is important to the functionality of its environment. As previously stated, a decline in genetic diversity leades to a decline in biodiversity, the loss of a species or the majority of it means changes in the environment, which leades to adaption among the species left, whether that be for better or for worse, but I have yet to see a disruption of that magnitude return a positive product.

Posted by Thomas Flores (2)

Acclimatization: the Human Body’s Greatest Defense.

Have you participated in any sport team back in high school? Or do you have any friends who are part of the school team and train hard everyday after school? Chances are you have probably heard of some athletes living at high altitude in order to attain a better cardiopulmonary system. This is called the “Live High, Train Low” theory. You might be wondering how this training strategy is utilized by athletes and how can our bodies are able to adapt and function to such a low oxygen level environment.

Lets take a look at the high altitude environment. For instance lets take a look at Alpine, Arizona which is located at an elevation of 8,000 feet (~2,500m). The amount of oxygen is significantly less than other places at sea level. The amount of O2 that is required for a runner to run at sea level is the equivalent amount of O2 that is required to an equivalent distance at Alpine, so you can see that it will take a lot more difficulty for the runner to run at Alpine compared to running at sea level.

The ideology of “Live High, Train Low” is to increase both the mass of hemoglobin and red blood cell volume in the body. Hemoglobin is the oxygen-transporter located in red blood cells. Oxygenated blood is pumped to muscles and organs all throughout the body in order to maintain daily bodily functions and activities, especially during periods of exercise.  Initially, when athletes first arrive at a high altitude environment they will begin to breathe harder and their heart rate will increase significantly in response to the scarce amount of O2 available, as their bodies are accustomed to sea level conditions where there is more available O2. 

Within a few days of living at high altitude the athlete’s body will begin to acclimate to the new environment, and as a result their breathing and heart rate will return to basal levels. According to ScienceDaily, a research team, led by B.D. Levine, worked with a group of track and cross-country runners to conduct an experiment to see how the “Live High, Train Low” training method affected their performance at different levels of high altitudes. The result of this study showed that the runners had an optimal acclimatization when living at altitude range between 2000m to 2500m.

It is amazing how we are capable of adapting to a range of different living environments. Having the ability of acclimatization is the human body’s greatest defense against abiotic disadvantages, such as global warming.

Posted by Yim Hui

New Methods May Solve Stem Cell Ethics Problem

Stem cells come in a variety of forms and have a range of functions. Pluripotent stem cells can differentiate into any type of cell, but have to specialize after their initial division. For example, a pluripotent stem cell can become a blood cell, a heart cell, a neuron, or a skin cell, however, once it becomes a skin cell, it no longer possesses the ability to differentiate into another type of cell. An entire organism cannot be developed using pluripotent stem cells. Totipotent stem cells can produce all types of differentiated cells and can develop into an entire organism. The most useful totipotent stem cells are embryonic stem cells. The ability to reprogram cells into a totipotent state and utilize their abilities to advance medicine and science is the ultimate goal of researchers. Unfortunately, pluripotent stem cells are difficult to make. They require an adult stem cell or a differentiated cell (capable of reproducing) to be reprogrammed into an induced-pluripotent state allowing it, once again, to differentiate into another type of specialized cell. The same process cannot induce a totipotent state as it can a pluripotent state. 

Researchers have discovered an effective method of inducing cells to this stem-like pluripotent state by regulating gene expression in cells with four factors. These factors are known as the Yamanaka factors. More recently, a group of researchers from RIKEN in Japan have identified a pair of histone proteins, in combination with the Yamanaka cocktail, that dramatically enhance the production of iPS cells and may be the key to generating induced totipotent stem cells. The 2014 article states, “The study demonstrates that, when added to the Yamanaka cocktail to reprogram mouse fibroblasts, the duo TH2A/TH2B increases the efficiency of iPSC cell generation about twentyfold and the speed of the process two- to threefold. And TH2A and TH2B function as substitutes for two of the Yamanaka factors (Sox2 and c-Myc).” The researchers believe the two histone proteins are utilizing a different pathways which allow for better efficiency and stability. Another method has recently been discovered for inducing pluripotent stem cells from adult stem cells by subjecting them to sublethal pressures and low pH. This causes extreme stress to the cells and essentially forces them to reset. From this state, they can be reprogrammed into a variety of other cells. Both methods have revolutionized the production of pluripotent stem cells and may help to discover a way to program lasting totipotent stem cells. 

These new methods benefit researchers in the ethical debate over stem cells. As mentioned before, manipulating and utilizing totipotent stem cells is the ultimate goal of researchers, but obtaining these cells from human embryos presents a significant moral and ethical problem (especially when previous methods have produced some not-so-savory results). Creating viable totipotent stem cells from stable pluripotent stem cells using these new methods could put an end to the ethical dilemma by completely avoiding the use of embryonic stem cells.

posted by Maxwell Liner (2)

Advancements in Bioengineering Leads to New Prosthesis that Lets Users Touch Again

I honestly can’t imagine what it would be like to lose the use of one of my hands. They are so fundamentally important to most of my everyday tasks that the thought of having to operate without one of them is traumatic in and of itself. Apparently I’m not the only one who thinks this way as a group of scientists in Italy are currently trying to come up with a new and better prosthesis. While current prosthetics are impressive they lack one of the most important aspects of a biological hand – feedback. At the current level of technology the best a prosthesis can do is respond to certain impulses that originate in the upper shoulder allowing for automated movement, and in more advanced models they can even produce variations in the amount of pressure exerted by the mechanical arm. However they cannot relay any of the information from the hand back to the user. Up until now scientists have had difficulty sending information on through the nervous system and back up to the brain. If a recent success is any indication though this last hurdle might have been overcome. 

A team in Italy thinks they might have come up with a solution to the feedback problem by surgically grafting tiny probes onto nerve receptors in the patient’s upper arm, and then electronically stimulating the probes. The mechanical arm can then pass on information through sensors embedded within it and let the user know details about the object that they are touching. BBC recently wrote an article about the paper that the team of scientists published. In the article BBC describes how the patient was able to not only receive feedback from the hand but that it was intuitive and he was quickly able to identify the stiffness objects that he was holding as well as vary the amount of pressure that was exerted. This level of feedback would allow the wearer to interpret the world around him without the constant need to supervise his prosthetic arm. Narrowing the gap between a biological hand and prostheses. While this new technology is still very much within the clinical trial phase that didn’t stop the patient from pronouncing he was ready to sign up for the first commercially available unit. It should be noted that the bionic hand itself is not the focus of this excitement; touch sensors and pressure variation have existed for some time. Instead these new changes have been brought about through software that can interpret the information from the sensors and pass that on to the custom made implantable electrodes.

It is amazing to think about how this might revolutionize the prosthetic industry and potential recovery of those affected. It is still a long way off from this sort of technology being available for commercial use but nonetheless it’s exciting to think about the progress that we’ve made. The bionic hand of science fiction lore is now more of a reality than ever before.

Posted by Kirk MacKinnon (2)

Who Turned on the Light?

      In our brains, neurons are continuously sending and accepting messages, thus communicating with one another. With so many different networks of neurons, its no wonder scientists desire to understand how each type of neuron plays a role in the functioning of the brain.  By developing the proper techniques to comprehend neuron roles and their functions, we can finally understand how a disease abnormality affects the brain.

      Karl Deisseroth, a member of the bioengineering and psychiatry facilities at Stanford University, has given neuroscientists a new look into the nervous system. Through his technique of using optogenetics, which combines optics and genetics to control well-defined events within specific cells, we can genetically modify neurons to either activate or deactivate when shining flashes of LED light. For example, by expressing channelrhodopsin-2 and turning on a blue LED light in a mouse, researchers can influence it to start running in circles.

       With more insight on the nervous system, patients suffering from psychiatric diseases could receive better treatments or possibly a cure. One very common psychiatric disease is schizophrenia, which relies heavily on the release time of dopamine. If abnormal levels of dopamine are present within the brain, the person will suffer from hallucinations. At the University of California San Francisco, researchers were able to use optogenetics to manipulate the signaling of dopamine neuron activity in animal test subjects. Their results showed that the stimulation of dopamine neurons at specific times could alter learning prediction errors and mimic prediction errors. This caused a long lasting impact on the reward seeking behavior of the test subject. By observing the behavioral responses from dopamine signaling, researchers were able to learn the role of dopamine in prediction error learning. Even more importantly, they were able to show how crucial dopamine signaling is in the brain. With these kinds of breakthroughs, psychologists can begin to offer better treatments for patients with schizophrenia.

Posted by Lindsey Janof (2)