In the article ‘Jumping
Genes’ May Contribute to Aging-Related Brain Defects, scientists found that
the number of transposons in the brains of fruit flies increases as they get
older. Transposons are also called jumping genes because they transpose
themselves into another part of the genome. This can cause fatal defects.
Another article on transposons called Rare
Form of Active ‘Jumping Genes’ Found in Mammals states that:
Many organisms have developed systems to decrease the
frequency at which jumping genes move, Craig says. Such systems are a component
of immunity, protecting mammals from retroviruses, as well as from the risk
that jumping genes will wreak havoc by interrupting an important gene.
It is believed that transposons have a role in brain development,
but can cause harm later on. Transposons accumulate as flies grow older. In fruit flies, Ago2 protects against transposon
activity. When scientists blocked the Ago2 in young flies, they found that the
young flies had the same amount of transposons as much older flies. The young
flies were then found to have defects in long-term memory that are usually
found in much older flies. The young flies also had shorter life spans as
a result of the increase in active transposons. Scientists believe that transposons
may be accountable for age-related neurodegeneration. This is an important
discovery because it can lead to an understanding of aging, brain development,
and brain defects.
An article in the NY TIMES, Why Can Some Kids Handle Pressure While Other Fall Apart, explains that there might be a genetic component. Today, a student’s academic future weighs so heavy on standardized tests in grade school to achievement test for college. The message students are getting is that class work no longer counts and what count are the standardized tests. There is a genetic component to a person’s response to competitive pressure. The gene COMT could tell us why some thrive under pressure while other melt. COMT codes for the enzyme that clears dopamine from the prefrontal cortex, the part of the brain that makes decisions, plans, and anticipates consequences and fixes conflict.
There are two COMT variations of the gene, one builds enzymes that remove the dopamine slowly, and the other builds enzymes that remove the dopamine very fast. A person has one or the other variation, or a combination of the COMT variations. Experiments have shown that the variation with slow moving enzymes have advantages while performing cognitive tasks and this advantage gets better with education. While people with the fast moving enzymes are lazy and the enzyme might remove too much dopamine. These results might have you think that you only want slow moving enzymes, but the slow enzymes are triggered by stress.
We inherit one COMT gene from out father and one from our mother, so most of us have a mixed variation. The fast enzymes are the Warriors and the slow enzymes are the Worriers, to survive through evolution we need both Warriors and Worriers. There are military studies looking at COMT gene, possibly connecting it to post-traumatic stress disorder and combat performance and well being. Navy Seals are looking are pilots to see what variation, and about a third were Worries.
After reading this article, I thought what does it have to do with genetics, then I thought, well over time these creatures have genetically developed into hunting professionals. Something must genetically be involved in order for dragonflies to be as quick and predacious as they are. In the article it talks about how their brain is much smaller than humans, obviously, with less than a million neurons working like a human brain of 100 billion neurons. The article tells the reader that dainty dragonfly kills 95% of its prey midair, as compared to a lion only catching 25% of pursued prey. I made a mental link and asked myself the question “genetically what does the dragonfly contain as compared to a beetle, and what is so different about it’s behavior?”
For over a hundred years, farmers used the concept of heterosis to increase crop yields. To take the most advantage of increased productivity, farmers cross two distinct lines of corn to produce a variety that performs much better than either of the two original strains. Much works has been done to study what lineages produce various types of corn, such as field corn and sweet corn. However, for all of the work that has done with corn hybrids, the genetic mechanism that makes this all possible remains a mystery – until now.
According to Science Daily, a research team comprised of individuals from the University of Bonn, Iowa State University, and the Max Plank Institute has proposed a genetic reason as to why heterosis works. Through state-of-the-art genetic sequencing technology, the researchers discovered genetic fingerprints suggesting that hybrid plants have more active genes than purelines. The increase in the amount of active genes allows hybrid plants to be more productive.
Perhaps the most exciting part of the article is its application to the real world. As food prices – especially corn prices – rise higher every day, there would be a great worldwide benefit if the researchers’ work could be used to produce corn crops with higher yields. Not only is corn used for human consumption, but it is also used for animal feed and biofuels as well. The researchers’ findings has the potential to have a major impact in the global economy.
About 73 percent of all genetic variation in humans has occurred in the last 5,000 years. According to a study published in Nature on November 28 co-written by Joshua Akey of the University of Washington, “Most of the mutations that we found arose in the last 200 generations or so. There hasn’t been much time for random change or deterministic change through natural selection. We have a repository of all this new variation for humanity to use as a substrate. In a way, we’re more evolvable now than at any time in our history.” In most studies of genetic variation, researchers estimated the age of more than one million variants of out DNA code found across human populations and found the majority to be relatively young. This was caused by a period characterized by both narrow reproductive bottlenecks and sudden, enormous population growth. As a consequence for the rapid growth and accumulation in gene variants, Akey’s group found that 86% of varients that seem to be deleterious are less than 10,000 years old, and many of them only existed for the last millennium.
One of the reasons for these large percentiles is due to the rapid population growth. 10,000 years ago at the end of the last ice age, there were about 5 million humans on earth and now there are 7 billion. During reproduction, random variations emerge and if multiplied across humanity’s expanding numbers, than an enormous amount of variation is generated. Natural selection never stopped acting and new mutations with especially beneficial effects, such as lactose tolerance, still spread rapidly, while those with immediately harmful consequences likely vanished within a few generations of appearing. But most variation has small, subtle effects. “Population growth is happening so fast that selection is having a hard time keeping up with the new, deleterious alleles,” said Akey. One of the factors that complicate natural selection in current times is the fact that it is not longer as natural as it used to be. These theoretical models do not account for culture and technology, which are two strong forces with major influences. As of now, the use of reproductive technologies is being studied to see if they ease selection pressure or make them more intense.
It seems common sense to me that evolution is still occurring, especially with the rapid growth that the population has experienced within the last few thousand years. As an organism, we were built to adapt and survive in some way or another, but the fact that so many deleterious mutations have occurred is amazing. I am curious if this is true with other species that have yet to be studied, or if it is due to the fact of how we have changed our natural eating habits and sexual reproduction through technology. Whatever the true cause is, I have always wondered what humans would be like in another 1,000 or 2,000 years and if any changes would even be noticeable. I hope more studies like these can predict what will happen to the human population within the next millennium.
With the spirit of the holiday still high, HealthDay News reports that the turkey you ate was greatly different from its ancestors in terms of genetic variation. The U.S. Department of Agriculture formed a team that compared the genetic diversity of domestic turkeys bred for Thanksgiving and their wild-roaming Mexican ancestors. This was completed by comparing the genomes of several types of domestic turkeys and the genomes of three Mexican wild turkeys. The genomes of the wild turkeys were collected in 1899 and were specimens of the Smithsonian National Museum of Natural History.
They found that the genetic variation in the domestic turkeys is much lower than that of the ancestral turkeys. Not only that, but the domestic turkeys have less genetic variation than other livestock breeds, including domestic pigs and chickens. The domestic turkey’s reduced variation affects the body size and breast muscle development, according to the article. The ancestral turkeys were transported and domesticated by the Europeans more than 100 years ago. Throughout all that time, many different varieties of the turkey were created. This selection in domestication reduced the level of variation. Unfortunately, this decrease in genetic variation may affect the holidays in the future if some unforseen problem arises.
While this is not nearly the only animal to have gone through such domestication, it clearly shows that we as humans have a great power. It is interesting to see how much control we have over breeding animals and plants just to suit our own needs and wants as humans. Who knows what the world will be like in another 100 years as we continue to control the environment around us.
It has been known for a while that substantial alcoholic drinking increases the risk of birth defects or may negatively affect the child in other ways, but now studies show that even moderate drinking can play a role in the intelligence of a child. There are four genetic variations that control the enzymatic ability to metabolize ethanol, some of which metabolize faster than others. These differences in metabolism indicate about how long the alcohol levels will be high for (so basically, the slower the metabolizing, the more likely one is to be considered a “lightweight”). After analyzing the genes of over 4,000 mothers during the course of their pregnancies, it was found that children of the mothers who consumed between one and six drinks a week had lower IQ scores by the time they were eight years old.
All four of the genetic variations were present in the study of the children, and these alcohol-metabolizing genes were related to the IQ’s identified. For each variation the children had, their IQ scores were two points lower. This data was compared against children whose mothers did not consume any alcohol during pregnancy, and there was no significant effect on the IQ’s. The observations made lead to conclude that alcohol consumed (whether moderate or substantial) during pregnancy has an effect on the future IQ of the fetus.
As ridiculous as it may sound, I never actually realized that genetic variations played a role in how ones body metabolizes alcohol/ethanol. Also, although I did always believe alcohol during pregnancy would always have an effect on the future child, I am somewhat surprised that all it takes for there to be an effect is one glass a week. Because something like this can so easily risk harm to or lower the IQ of a fetus, it makes me wonder if there are any other chemicals/nutrients that could affect a fetus so quickly and without much effort, but in the opposite way. So is there something similar to ethanol that could be consumed once a week throughout pregnancy that would enhance a fetus’ IQ?
According to Science Daily, a research team headed by University of California, Davis professor Charles H. Langley has documented evidence of natural selection in fruit flies, also known as Drosophila melanogaster. Like humans, fruit flies originated in Africa tens of thousands of years ago. Similarly, while genetically diverse populations of fruit flies still exist in Africa, many distinct lines of fruit flies now exist in every part of the world. Some fruit flies have evolved to adapt to certain specialized environments. For example, a certain strain of fruit fly makes its home near breweries. Overall, Langley’s research describes the genomes of over 200 strains of D. melanogaster.
D. melanogaster is a model organism that is often used to study genetics. Because fruit flies produce many offspring and go through many generations in a short amount of time, these tiny insects are often used for genetic research. Langley and his colleagues hoped that their work on D. melanogaster would be used as a precursor to studying natural selection and genetic variation in humans. Langley’s team is not the first one who proposed using D. melanogaster to learn about human evolution; other scientists have chosen the same path in the past.
What is most interesting about Langley’s research is that the mixing of D. melanogaster populations mirrors the mixing of human populations in the world. Due to globalization and advances in technology, human beings are more mobile than before. Many people have chosen to settle in places that are far away from the lands of their grandparents. Likewise, technology and globalism has allowed – unintentionally, of course – European fruit flies to travel to Africa and meet their distant cousins. Perhaps further study on the genetic variation and natural selection of fruit flies will give hints about the history of the human race.
Eye color may be an indicator of whether a person is high risk for certain skin diseases. At University of Colorado School of Medicine, a study has shown that people with blue eyes are likely to have vitiligo, an autoimuune skin disease causes pigment loss of irregular white patches of skin and the hair. People with brown eyes are less likey to have melanoma, which is a dangerous kind of skin cancer. In the Journal of Natural Genetics, researchers look at non-Hispanic European ancestry, 3,000 new genes predispose for vitiligo. 27 percent had blue/gray eyes, 43 percent had tan/brown eyes, and 30 percent had green/hazel eyes. Americans non-Hispanican European ancestry had 52 percent blue/gray eyes, 27 percen tan/brown eyes, and 22 percent green/haxel eyes. Richard Spritiz M.D. of Human Medical Genetics said vitiligo and melanoma are polar opposite. Some of the same genetic variations make one more likely to have vitiligo, and less likely to have melanoma or vice versa. Vitiligo disease attacks the normal pigment cells, but by over activity by one’s immune system searches out and destroys early cancerous melanoma cells. People with vitiligo are at a higher risk of having thyroid disease, type 1 diabetes, arthritis, and lupus. Dr. Spritz says there must be some genes that push towards autoimmune diseases, which other genes are enviromental triggers determine which autoimmune disease occurs and when.
I think that this is interesting how by a certain eye color a person is more likely to be prone to a certain disease. I am curious on how researchers can detect this but have not came up with a solution to help prevent this.
About 300,000 years ago people didn’t have many options when it came to food and nutrients. That’s why the human body automatically produced large amounts of Omega-3 and Omega-6 fatty acids. This adaptation actually was useful and helpful for humans then. However, this adaptation in today’s life would actually result in disorders like cardiovascular disease. The reason being that now you can get these fatty acids in vegetable oils or from eating fish easily. There are two key enzymes that do produce the fatty acids from vegetable oils and we are the only humans that actually have that unique genetic variant. So having to obtain these fatty acids easily in our everyday diet and our bodies producing can lead to many issues to your bodies; since we shouldn’t have too much of it. This article actually make sense cause back then we really didn’t have much when it came to food or surviving so we were lucky enough that our bodies were able naturally make these fatty acids to help us survive but who could have thought that would actually hurt us now just because we have many types of food that we can obtain fatty acids from.