Are humans changing diversity worldwide?

It is no secret that the human population has impacted the environment and the various species on earth.  Researchers at McGill University states that animal diversity is changing due to loss of their environment and the increase of the human population. The biologists of McGill University pulled information from the largest genetic data repositories available and from the results came to a conclusion that while the human do impact the genetic diversity in animals, the results are not all negative. Data trends shows human influences increase the genetic diversity in certain species while decreases the diversity in other species.

Personally, I believe the genetic diversity in species are decreasing at a faster rate then it is increasing. I think a large percentage of the increase in genetic diversity is due to human interference, an example being breeding new corn strands. The genetic diversity increase are happening naturally but rather scientifically induced. All in all I believe the human population has a rather negative effect on genetic diversity.

Links:
https://www.sciencedaily.com/releases/2019/10/191022112156.htm
https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13394

Genetic Variant 7R Has Been Identified as Potential "Explorer" Gene

While humans have made many notable strides in evolutionary differences between our fellow mammals – opposable thumbs, brain size and development, advanced language, etc – one notable stride has been gaining the attention of evolutionary biologists, neurologists, anthropologists, and geneticists alike. The expansion and exploration of humanity has fallen under the microscope and the research in this area is ever-growing. As reported by none other than National Geographic (who better?), multiple fields of scientists are examining human exploration, including geneticists. In recent studies, geneticists have been examining the effects of a variation on the DRD4 gene, a gene which influences dopamine, an important neurotransmitter in regards to learning, rewards, excitement, and pleasure. The variant in question, DRD4-7R, has been linked to Attention Deficit Hyperactivity Disorder (ADHD), and is starting to get linked to the exploratory tendency of human nature. In a broad sense, human studies have correlated the presence of the 7R variation to restlessness, curiosity, and higher inclination towards adventure and change. In a larger study  conducted by the University of California, the variant 7R was found more commonly in individuals whose ancestors were highly migratory than those who hailed from more sedentary populations. Other studies have found R7 to be more common in individuals whose ancestors had longer tracks of migration, individuals in modern-day migratory groups who are more physically fit and well-nourished when migrating often as opposed to poorly-nourished individuals in settled villages, and even more common in individuals who have lived to old age and exercised well during their lifetime (both in humans and mice) . While multiple studies do come to the conclusion that there is a correlation of the variant in individuals whose ancestors travel and who benefit well from enriching environments and movement in their lifetime, most professionals agree that human exploration, while unique even among hominids (not even Neanderthals were known to move far from their established territories) , cannot be placed solely onto a single gene. Humans are the only mammal known to explore beyond established territories without the need to do so (i.e. depleted resources, following prey, etc.), but there have been a lot of physical adaptations that have led to this unique trend. The change from quadrupedal to bipedal movement allowed humans to expand their territorial range and increase their endurance; the expansion of the brain and the delay in maturation has allowed for the increase in creative thinking as well as intellect that lead to innovative tools and understanding of scenario-based potential outcomes; the rather un-matched dexterity of human hands allowed the human imagination to expand and build tools to aid in travel. While the R7 gene may correlate to hyperactivity and perhaps to the urge to move and maybe even travel, there are many factors that have led to the expansion and exploration that is inherent in humanity.

Transgender Monkeys Genetically Modified are the New Way to Go

For two years Scientist Anthony Chan created genetically modified transgender monkeys. In his experiment, he found that 3 out of the 5 monkeys developed Huntington Disease. The symptoms were so severe the monkeys has to be killed within the month of having the disease. Chan is hoping the primates will be the future models instead of mice. Chan believes that primates will accelerate basic research in neuroscience. This will help researchers mad and text the complex neural circuits underlying the behavior that cannot be found in simpler organisms. Monkeys are already superior to mice since they can replicate disorders easier in monkeys than mice like autism, Alzheimer, and schizophrenia. Mice also have failed to fully show how drugs will actually effect human beings. Mice however are cheaper and easier to obtain. They also show signs faster for researchers to observe.

Its been known that humans and primates can be compared because they carry similar traits. Now the idea of using primates to conduct neuroscience experiments is interesting and exciting. The use of primates could help researchers better understand disorders and diseases who do not have cures - just yet.


http://www.scientificamerican.com/article.cfm?id=precision-gene-editing-paves-way-for-transgenic-monkeys

Nature and Nurture: The Role of Epigenetic “Marks” on Chromosomes in Mental Illnesses

Recent research has shown that a person’s experiences may contribute to mental illness by causing epigenetic changes (as opposed to simply genetic influences), which turn genes "on" or "off" without changing the genes themselves. The causes for neurological problems like addiction, depression, autism, schizophrenia, and the like seem to be mostly genetic, but the addition of environmental factors such as drug use or high amounts of stress in a person’s lifetime play an equally strong role. The way our experiences are processed in the brain has to do with nerve cells, which exchange information by releasing and identifying chemicals called neurotransmitters. It has been discovered that neurotransmitters can activate or inhibit different nerve cells and then switch a group of responsive genes on or off -- over time, the particular genes a neurotransmitter affects can help in predicting how a nerve cell will respond to an experience, which then determines how an individual behaves.

[caption id="attachment_2748" align="alignright" width="239" caption="Image source: Nestler, Eric J. "Hidden Switches in the Mind." Scientific American Dec. 2011: 79. Print."][/caption]

However, the aforementioned effects of neurotransmitters on behavior are not permanent, which is why the role of epigenetic marks are so interesting in that they do cause more lasting behavioral changes. Essentially, these marks are chemical tags that are located on either DNA or histone proteins around which DNA is normally wrapped on genes, and they influence how tightly packed chromatin should be. (The more tightly wrapped DNA strands are around histone proteins, the more inactive genes are and the less likely they are to turn on. When a protein needs to be made, however, the section of DNA the gene that is needed to create it is on unfurls slightly so that it can be transcibed into a strand of RNA and the encoded protein can be produced.) These epigenetic changes are made by different enzymes, some of which add chemical tags, and others which remove them; researcher C. David Allis calls them the "writers" and "erasers," respectively, of the epigenetic code.

Studies have been done showing the impact of epigenetic markers on various types of behavior, including maternal behavior. These studies were conducted with rats and showed that epigenetically-affected behavior can be passed down in generations by affecting only the pups', or baby rats', brains because they are born with methyl marks on particular genes that enhance sensitivity to stress and if they are raised by relaxed, nurturing mothers, these methyl groups disappear and they are calmer pups and later, parents; however, if they are raised by passive, fearful mothers, then their genes actually acquire more methyl groups, and they grow up to be similarly passive, fearful parents themselves. Using this information is and will continue to be important in the future to improve methods for treating various psychiatric problems by developing drugs and attempting to ascertain to what degree epigenetic changes that occur with these psychiatric conditions are heritable.

For more information about the article used as the primary source for this post, listen to the author's own thoughts about it.