This is the place I (Mr. Toyos) will be using to keep you (my students) informed of the latest developments in the scientific community, linking the topics discussed in class with related articles, websites and any other resource available.
I encourage you to make comments using the link below the posts, start discussions and even bring them to class.
In an analysis of commercially available mineral waters, researchers
found evidence of estrogenic compounds leaching out of the plastic
packaging into the water. What’s also shocking, these chemicals result in an increased development of embryos in the New
Zealand mud snail. These findings, show for the first time that
substances leaching out of plastic food packaging materials act as
functional estrogens.They analyzed 20 brands of mineral water available in Germany – nine
bottled in glass, nine bottled in plastic and two bottled in composite
packaging (paperboard boxes coated with an inner plastic film). The
researchers took water samples from the bottles and tested them for the
presence of estrogenic chemicals. They then carried out a
reproduction test with the New Zealand mud snail to determine the source
and potency of the man made estrogen (xenoestrogen). The water samples from the plastic and composite packaging showed 50% more cotamination. Also, the snails in the plastic bottles produced twice the number of embryos compared to the snails in the glass bottles. These results demonstrate contamination of mineral water
with potent man-made estrogens that originate from compounds
leaching out of the plastic packaging material. The researchers conclude: “We must have identified just the tip of the
iceberg in that plastic packaging may be a major source of xenohormone
contamination of many other edibles. Our findings provide an insight
into the potential exposure to endocrine-disrupting chemicals due to
unexpected sources of contamination.”
This was a mix of hypothesis and discovery based science. The contamination problem was discovered during an analysis of mineral waters. The snail and water sample tests were hypothesis based.
This is useful information because it alerts people to the problem of man-made hormones in bottled water. It might also further encourage students to use the refillable bottle stations at Saint Johns.
Thursday, May 10, 2012
A Step Toward a Saliva Test for Cancer
In a recent discovery, which was announced during the 242nd National Meeting & Exposition of the American Chemical Society (ACS), scientist said that there may be away to test the amount of potential carcinogens in the DNA of someones saliva. This could lead to the knowledge of the probability of someone getting cancer of any other disease. It can also show progress of a cancer treatment or to inform high risk patients on how they can prevent themselves from getting a disease. They found this because a DNA adduct begins to form once a cancer causing mutation is found in a DNA. The new test measures the levels of five Key DNA adducts and this can lead to the test that will tell the probability of someone having cancer or other serious diseases.
This is a type of discovery science because they found that the DNA might be able to help discover these new techniques to find cancer. This can help humans find diseases and also might help cure them faster and save more lives.
Journal: Science Daily Author: Unspecified Date: August 31, 2011
Tasmanian devils are in danger of being wiped out by a
contagious facial cancer that has been spreading via live cancer cells through
bites. This cancer has plagued the animal’s population for more than a decade
now, having spread from the original infected female 15 years ago. Genetic
sequences show that all tumors affecting the population today contain cells
from the originally infected devil. Researcher Elizabeth Murchison, from the
Wellcome Trust Sanger Institute, calls her the immortal devil. The Tasmanian
devil genome revealed why the cancer hasn’t killed off the species yet. As it
turns out, some devils show resistance to at least two strains of the cancer. However,
the Tasmanian devil’s cancer has more than 17,000 mutations. “Sequencing the
genome of this cancer has allowed us to catalogue the mutations that caused
this cancer to arise and to persist,” Murchison said. Information acquired from
studying the genomes could point the way to targeted cancer drugs. Scientists
hope the Tasmanian devil cancer can prepare them for the rare likelihood that
there is ever a contagious cancer in humans.
This is
discovery based science as no hypothesis was made, and the article is simply
reporting the findings.
This discovery helps humans in the
way that it provides new information in the fight against cancer, and is
helping scientists find ways to fight against a contagious cancer that affects
a population, in the event that there is ever such a cancer that affects human
beings.
Title: Contagious Cancer: Genome Study Reveals How Tasmanian
Devil Cancer Has Spread
After thirteen years of development, the Genetic Information Nondiscrimination Act (GINA)was passed in May of 2008. This innovative law prevents health insurance companies and employers from denying coverage or jobs because of an individual's genetic predisposition to a certain disease. In this way, otherwise healthy people are safeguarded from based on their DNA.
This article cannot accurately be described as either hypothesis or discovery science but is closer to the latter as no experiment was conducted. This innovative legislation is highly significant to mankind as it may potentially provide great benefits as medical sciences advance. With this protection from the possibility of discrimination, individuals may be more inclined to engage in testing which will identify possible genetic liabilities, such as an elevated risk of developing heart disease. This knowledge of genetic predispositions may, in turn, lead to more effective preventive treatments.
Title: A New Law Bans Genetic Discrimination
Journal: Discover Magazine
Author: Karen Wright
Date Published: December 17, 2008
Researchers
at Zucker Hillside Hospital and Feinstein Institute for Medical Research found
a gene that increases weight gain in those that are treated with antipsychotic
drugs, used to treat psychotic disorders. In this study they used
second-generation antipsychotics or SGAs, which are commonly used to treat many
psychotic and non-psychotic disorders. In the study researchers first evaluated
a group of patients treated for the first time with antipsychotics. Then they
replicated the result in three independent groups of patients who were in
psychiatric hospitals. The gene identified to increase weight gain was MC4R or
melancortin-4 receptor. Originally it had been linked to obesity and type-2
diabetes. In this new study, patients gained up to 20 pounds on the treatment. The
article is an example of hypothesis-based science because an experiment or
study was done. The study gives the possibility of being able to identify who
is at great risk for severe weight gain due to the antipsychotic treatment;
therefore it is helpful in relieving those who are at risk. Instead they could receive
more intensive or alternative treatment that would reduce the potential for
weight gain. Currently they are conducting studies to find that type of treatment.
Title of
Article: Researchers discover gene that leads to severe weight gain with
antipsychotic treatment Journal: Biology
News Net Date: May 7,
2012
On March 26, 2012 at
12:16 p.m., Peng Peng, the World’s first handmade cloned transgenic sheep was
born in China. Chinese scientists from BGI, Institute of Genetics and
Developmental Biology, Chinese Academy of Sciences and Shihezi University successfully
made Peng Peng. They used a simplified technique called handmade cloning. It
uses much simpler equipment, procedures and it is cheaper that other methods of
cloning. They say that so far he “is developing normally and appears healthy”
(Dr. Yutao Du). This project had been ongoing for about two years and faced
some difficulties. For example, only very few of the reconstructed embryos are
able to develop into healthy offspring, they had to adjust to special climate
and deal with very basic instruments/materials. This modification could result
better meat quality by increasing the unsaturated fatty acid content. The ω-3PUFAs
that are added to the sheep reduce the risk of coronary heart disease and bran,
eye and neuron development. Since then, other species have been cloned using
this technique.
This is hypothesis
based science because the scientists had to conduct many experiments throughout
the two year process, and had to test their hypothesis until finally succeeding.
This accomplishment
affects humans because it allows us to intake ω-3PUFAs by drinking milk or
eating meat and has many medical benefits, like reducing the risk of heart
diseases. Also, this could help save endangered species and make medicines for
human diseases through transgenic animals.
Source: ScienceDaily
author: n/a
date: April 19, 2012
BGI Shenzhen. "World's first handmade cloned transgenic sheep born in China." ScienceDaily, 19 Apr. 2012. Web. 9 May 2012
One in Six Cancer Worldwide are Caused by Infection
The Lancet Oncology review recently looked at what started some 27 cancers in multiple countries, and came across the conclusion that four main infections (human papillomaviruses, Helicobacter pylori and hepatitis B and C) are are major causes for cervical, gut and liver cancers.
These cases usually happen in the wild. But even so, it does happen in more civilized areas of the world. This is hypothesis-based science, since the scientists and researchers were able to pin point what started certain cancers.
Knowing that some cancers are caused by certain viruses is helpful to the human race because this way, one can vaccinate for those viruses in anticipation, and prevent that cancer. The problem, however, is that these viruses are more common in areas that don't have the vaccinations available. So it makes it easier to prevent getting the viruses in places where the viruses are already less common.
Title: One in Six Cancers Worldwide are Caused by Infection
Author: Michelle Roberts
Date published: May 9, 2012 6:31 am
Date read: May 9, 2012 10:50 am
59 scientists have made a new discovery that will change the way deadly breast cancer is to be treated. The study is the largest genetic analysis of what were thought to be triple negative breast cancer tumours. All 59 scientists entered the lab believing to find a similar gene. When the tests came back, they had found that no two genomes were the same, nor even similar. Steven Jones, the co-author of the study, stated "Seeing these tumours at a molecular level has taught us we're dealing with a continuum of different types of breast cancer here, not just one". Triple negative breast cancer lacks surface cell receptors for estrogen, progesterone and herceptin and targets 16% of women who developed breast cancer and targets those under 40. Scientists consider it the most deadly form of breast cancer because modern drugs do not respond well to it. This experiment is a discovery based science because the scientist expected to find a similar gene, but instead found something even more impacting. This experiment affects humans in a grand scale. Now that we know how triple negative breast cancer tumours look like, they can understand how to treat them better and hopefully save lives.
A genetic mutation in the geneDEC2 has proved to allow people to function on less sleep. People with this mutation have been able to function with only five to six hours of sleep. The mutation allows people to sleep more efficiently. In addition, they seem to have no negative effects to it. Although it is very rare, even among short sleepers, those involved in the discovery have said that they are trying to find a way to use it to benefit us in the future. This gene may be a key in helping those with sleeping disorders, or to simply help those who do not get enough sleep.
This is an example of hypothesis based science because experiments were conducted on mice to see the effect of the gene, and on people to see how common the mutation was.
Author: Katherine Harmon Title: Rare Genetic Mutation Lets Some People Function with Less Sleep Journal: Scientific American Date Published: August 13, 2009
RNA Editing Explains Mystery of the Antarctic Optopus
Octopi are a species who can be found in the coldest of waters, as well as the warmest. For this reason, scientists were shocked to find out that octopi living in the Antarctic as well as Caribbean octopi shared almost the exact same nervous system, that moved at the same rate. Usually the colder water would have slowed down the speed at which the nervous system of the organism worked. For years, scientists have attempted to figure out the reason for this strange development; now they know the answer. Scientists have found that edits are made to the creatures nerve cells, in order operate more efficiently in numbing water. Joshua Rosenthal, from the University of Puerto Rico Medical Sciences Campus, explains that something changes the way the instructions of the DNA are sent and interpreted by the bodies nerve cell building machinery. They realized that this occurred in the mRNA, which was edited different by it's editing enzyme. With the new edits, the nerve cells change the rate at which they open and close the "gate" that produces electrical impulses. In the Antarctic octopus, the opening and closing of the gate is more rapid, since cold slows down this rate. It is an important counteraction that allows the octopus to survive. This experiment was definitely a hypothesis based one. This is because scientists spent many years testing, observing and documenting the genes of these organisms. It is helpful to humans because it allows use to understand the inner workings of such elusive and interesting creatures.
Jason Bryant, commonly known as "Weeman", is a living example of a genetic mutation. He suffers from achondroplasia, which is a genetic disease that doesn't allow one's arm or leg bones to grow very much. He stands at 4'7" and his love for skateboarding somehow brought him into the hit series "Jackass". Achondroplasia dwarfism comes from a mutation in the fibroblast growth factor receptor 3 (FGFR3) gene located on chromosome 4, or it is passed down by a parent. However, if it comes from a mutation in the genes, it is an amino acid substitution that causes that gene to falter. The mutation causes the FGFR3 gene, which controls the bone growth from cartilage, particularly for longer bones (arm, leg, etc.), to not allow those bones to grow very long.
This is a hypothesis based science because scientists had to narrow the mutation down to which type of mutation it was and how it could be passed down.
This topic affects humans because it is a disease that occurs on humans and to have the knowledge of such disease brings a better understanding to the world.
Title: "Weeman", "Mutations in fibroblast growth-factor receptor 3 in sporadic cases of achondroplasia occur exclusively on the paternally derived chromosome."
Author: Reality TV Online, D J Wilkin, J K Szabo, R Cameron, S Henderson, G A Bellus, M L Mack, I Kaitila, J Loughlin, A Munnich, B Sykes, J Bonaventure, and C A Francomano
Most of the proteins and other molecules in our body can exist in two distinct forms that are mirror images of each other, but our body only prefers one of these forms. This is known as chirality. Thomas G. Mason has been exploring how and why this chirality arises. He said, "objects like our hands are chiral, while objects like regular triangles are achiral, meaning they dont have handedness to help them." These can be easily superimposed on top of one another. Still a mystery to scientists is the concept that only one of the two chiral forms can exist in one body. "Our bodies contain important molecules like proteins that overwhelmingly have one type of chirality," Mason said. "The other chiral form is essentially not found. I find that fascinating." In the image to the left, the colored outlines in the field of triangles indicate chiral super-structures having particular orientations. Mason says that the cause for this phenomenon is entropy. His group has shown for the first time that chiral structures can originate from physical entropic forces acting on uniform achiral particles.
This is an example of discovery science because the scientist, Thomas G. Mason, has been doing experiments on this for a while. This discovery benefits humans because it helps us understand why and how we each have a dominant, stronger hand. Even though some people can be ambidextrous, everybody has one hand that is clearly dominant to the other. One cannot be right handed and left handed at the same time.
University of California - Los Angeles. "Chemistry: Scientists unlock mystery of how 'handedness' arises in proteins, other functional molecules." ScienceDaily, 8 May 2012. Web. 9 May 2012.
A new study reveals that insomnia is actually produced by a gene that has been initially found in fruit flies. The scientists believe that it also applies to humans that also carry this mutation in the protein. Fruit flies, and humans, with this gene normally sleep two-thirds than normal and live shorter lives than those who have regular sleeping cycles. It also contributes to conditions such as high blood pressure and diabetes. The article states that even though humans and fruit flies are barely similar, the sleeping characteristics are most probably similar. This gene deprives people, and fruit flies, of their sleep and consequently entails chronic life-long sleep disorders. In the article it also mentions that “Dr. Nicholas Stavropoulos, of Rockefeller University said that ‘this work gives us several new clues about how sleep is controlled at the molecular level.’.”
The scientists that discovered the “insomnia” gene used hypothesis based science because they tested it on more than 20,000 fruit flies and they experienced the same mechanism in sleep disorder.
The findings of this gene are important to humans because it gives explanations to millions of people that suffer from chronic sleep disorders and insomnia. It is a step forward towards why insomnia exists in humans and in animals. This is one of many other conclusions that have been brought up as possible solutions to the reason why insomnia is present.
Bibliography
Title of article: Discovered: The 'insomnia' gene that means you sleep two-thirds less than normal (... and don't live as long)
Four percent of the people that live in Africa have DNA that comes from Neandertals. This is a result of interbreeding between Neanderatls and early modern humans. Scientist discovered this by looking at a Neandertal genome, which shows 60 percent of the entire genome. They used DNA that came from three Neandertal bones that are over 38,00 years old. They saw that twelve genome regions where non-Africans shows variants that were not seen in Africans and therefor came from Neandertals. Neandertals lived in Eurasia, not in Africa. They found that 10/12 variants in non-Africans came from Neanderatls. They saw that the Neandertal sequence was equally close to people from France, Papua NEw guinea and China. Scientist explain this by implying that their might have been interbreeding in the Middle East. They discovered that many people, besides Africans have some Neandertal inheritance.
Was the article you selected an example of discovery science or hypothesis based science? Explain This article is a hypothesis based science because scientist noticed patterns in genomes and then created a hypothesis that they then researched.
What importance does the research or findings have for humans? This research is important evidence for multi regional evolution. This helps to indicate which parts of the modern genome separates humans from all other living creatures. This may have helped modern humans adapt. These regions helped in the study of cognitive development, sperm movement, and the physiology of the skin. They still want to understand how these small changes to the modern human sequence impact the functioning of the genome regions.
About 50 years ago researchers discovered that the quantity of purple color in corn deviated from the accepted laws of heredity. However, this paramutation, or a genetic trait that, according to theory, should have been removed over the generations but has resurfaced in newer generations, remained unexplained. In 2006 Minoo Rassoulzadegan of Inserm in France and some of his colleagues noticed a similar occurrence of paramutations when working with mutant mice. A mutation in the Kit gene causes white pathces of fur to grow in certain areas on brown-coated mice. Researchers bred two heterozygous parents, each with one normal copy of the gene and one mutated copy of it. The scientists hypothesized that the offspring that inherited 2 normal copies of the gene should not have developed the white patches on their coats, but they did. In searching for an explanation to this phenomena, researchers noticed that the mutant mice had unusually low levels of regular RNA and higher levels of mRNA (messenger RNA), and the mRNA was found to have made its way into the sperm. When testing this hypothesis by injecting this RNA into embryos 50% of the offspring had the white patches. Although we still don't know why the RNA is having an effect on hereditary factors, this discovery may force biology textbooks to rewrite the chapters on the causes for genetic variations.
This experiment was an example of hypothesis-based science because the scientists noticed certain patterns and then based on previous knowledge made a hypothesis which they tested various times in order to find an explanatory result for their question.
Author: David Biello
Title of Article: Mouse Finding Violates Law of Heredity
How did the zebra get its stripes? The first thing that would come to mind would be an amusing and entertaining camouflage explanation. This would make sense if we lived in a black and white world in which zebras would basically fuse with their surroundings. But that is not the case. The reality of the situation is that the black and white stripes of the zebra are not the only important part of their skin coat, but also the arrangement and angles of the stripes.
In MANY places of the world, especially in Africa and Budapest, there is a big concentration of insects called Horseflies or Tabanids. These deliver nasty bites, carry countless diseases and (most annoying) distract gazing animals from feeding. "According to 'Horvath' the Tabanids are attracted to horizontally polarized light because reflections from water are horizontally polarized and aquatic insects use this phenomenon to identify stretches of water where they can mate and lay eggs. However, blood-sucking female Tabanids are also guided to victims by linearly polarized light reflected from their hides". Basically it means that these insects are attracted not only to horizontally arranged "lights", but they are also attracted to darker colors.
After several experiments with different kinds of horses to prove this, it has been concluded that the "flies" were not attracted to white horses; however, the brown and black horses were completely covered with bites.
Zebras have an arrangement of mostly vertically aligned stripes and those have a variety of black and white patterns in them. The flies are DEFINETELY not attracted to the color white. You might ask “but what about the black stripes?”. That’s when the arrangement of the stripes comes in. The stripes are arranged in a non-vertical position so that the flies are actually repelled by the positioning of the lines.
This is a hypothesis based discovery because the scientists involved in this experiment knew that the stripes had some sort of function (in the zebra), but they did not have clear what it was. They experimented on several horses and zebras, and concluded what they started their research for; the purpose of the stripes.
This discovery does not really have a direct importance for humans, but it is valuable knowledge and it could be helpful in future situations.
Born to Run: Humans will never win a sprint against your average quadruped. But our species is well-adapted for the marathon.
We have a right to conclude that, four our size, humans are pretty poor runners when it comes to chasing a cat that’s trying to avoid a bath. Were we excel is endurance running. Also, we run long distances at fast speeds. Joggers can do a mile in seven and half minutes while top marathoners can do five minute miles together for more than two hours. A quadruped of about 150 pounds takes nine and a half minutes. Good endurance runners are rare among animals.
But what evidence can support the idea that endurance running gave early humans an evolutionary advantage? Long legs and the long stride they enable are helpful to walking as well as to running. But running and walking are mechanically different gaits. A walking person, aided by gravity, acts as an inverted pendulum: the hip swings over the planted foot. A runner bounces along, aided by tendons and ligaments that act as springs, which alternately store and release energy. Also, endurance running requires more stabilization of the trunk than walking does. Members of the genus Homo have substantial gluteus maximus muscles and have large attachments from the hip to the base of the spine. In cave men fossils, the muscle has more limited area of attachment. Chimpanzees are gluteally challenged also. Large butt muscles make for efficient energy transfer during running by stabilizing each hip. But the muscles are not used for walking on level ground.
The shoulder of the chimp is well stabilized, tied to the spine and the head by many strong muscles. In humans, the shoulders are less robust because when we walk, our shoulders don’t move much. When we run, because of the loose attachment, the shoulders rotate strongly one way while the hips rotate the other, which keeps us in balance. We can also swing the upper body without rotating the head, so we can see where were going. Homo also has several “antibobblehead” adaptations that apes and cavemen lack. The first is a modification of semicircular canals, the organs in each ear that tell the brain which way is up. Three canals sit at right angles to each other in each inner ear. Two are enlarged in Homo, and the size makes it easier to sense, and to counteract, a moving head. An elastic ligament that runs from a ridge at the base of the skull to the base of the neck also damps the bobbing effect. Analougous ridge structures, to which damping ligaments can be attached, occur in dogs and horses, but not in the chimp. Bramble and Lieberman’s analysis makes corrections to the scientific picture of early humans. Our ancestors might have ranged across large distances in the heat of African dessert in relatively short spurts of long-distance running, as well as walking. They may have been trying to maximize the chance of encountering carrion before other scavengers did, or perhaps they were adapted to running down prey before spear throwers or bows were invented.
Scientific Article Analysis
Topic: Genetic traits in sexual organisms.
Find an article that discusses any genetic trait that is presented in any sexual organism; you can talk about particular characteristics, genetic defects, particular adaptations that enhance the survival of an organism, etc.
Read the article and type a one paragraph summary of the findings. Post your work on the Biotic-Blog (link), don’t forget to log in with your Gmail account.
Analysis
After the paragraph, identify the approach the researcher or group of researchers took to make their discovery.
·Was the article you selected an example of discovery science or hypothesis based science? Explain
My article is discovery science because we discovered the qualities of the tendons and shoulders of the chimps, the homo, and the cavemen.
·What importance does the research or findings have for humans?
It gives a good adaptation for survival and health.
The human body is filled with antibodies that fight invaders, cells that regenerate, and structures whose job is to ensure that the body runs smoothly. For instance, the structure myelin, is a material that surrounds the axons of our nerve cells, therefore, making them send signals. However, in demyelinatin diseases, myelin and oligodendrocytes that makes it, become damaged. As a result, in Caltech researches have found a way to help the brain replace injured oligodendrocytes and myelin. They have created a gene therapy used to produce new oligodendrocytes, which play an important role in an adult’s nervous system, from stem and progenitor cells. Benjamin Deverman, a postdoctoral in biology at Caltech described it as “…Using the brain’s own progenitor cells as a way to boost repair.” This therapy uses leukemia inhibitory factor (LIF) because it enables remyelination by stimulating oligodendrocyte progenitor cells to proliferate and make new oligodendrocytes. These researches conducted an experiment-using mouse and they said that when they gave LIF therapy, it not only triggered the proliferation of the progenitor cells, but allows them to differentiate into mature oligodendrocytes. Using LIF has some benefits; for instance, one avoids potential side effects that may appear when the therapy is introduced in the bloodstream. Moreover, it is also helpful for spinal-cord injury patients. Researches have not yet held a human clinical trial, but they plan to have a virus that will carry the genetic material, LIF, into the cells; however, they cannot control the virus, which makes it a little dangerous. As a result, Patterson and Deverman are attempting to develop viruses that can target LIF in specific cell types and turn it on and off externally, providing a means to regulate LIF levels.
This article is an example of hypothesis-based science because researchers conducted a clinical trial on mouse and observed how this gene therapy worked. In addition, they have come up with explanations to certain effects and causes of this gene therapy using LIF that have appeared on mice. This will greatly help human life because it will help human beings to allow the brain to replace damaged cells that play an extremely important role in the nervous system of adults.
California Institute of Technology. “Gene therapy boosts brain repair for demyelinatin diseases." ScienceDaily, 9 Feb. 2012. Web. 9 Feb. Page 1. 2012.http://www.sciencedaily.com/releases/2012/02/120209140208.htm
Researchers working with mice in Emory University discovered that a small manipulation in their genes can increase brain performance and boost memory. It is a gene that is present in both humans and mice. Pharmacologist John Hepler and his team studied CA2, a part of the hippocampus that, instead of participating in the learning and memory process, has neurons that are full of a protein that inhibits the communication between them. They found that mice bred to not have the gene for this protein, RGS14, did better in memory tests with no observable negative side effects. Serena Dudek, a neuroscientist, says if this gene that "makes us dumber" has remained with natural selection, then there must be some reason for it, and maybe the downside just hasn't been found. Neurobiologist Alcino Silva agrees, saying that when one thing is enhanced something else must be diminished.
This article presents an example of hypothesis science. The scientists were looking for something that affected memory (the protein), and then carried out experiments to see which gene produced it. Once they found it, they hypothesized that removing this gene would improve the memory of these mice. Their theory seems to have been correct so far. If this technique was perfected, and confirmed to have no negative side effects, the possibilities of applying it to human medicine would be endless. In the future, advanced treatments that target this gene or protein specifically could be used for learning or memory disabilities.
The article is about an experiment conducted by Stephen Kowalczykowski and Anthony Forget on how DNA strands find their exact match. For 50 years since James Watson and Francis Crick showed that DNA is a double helix of two strands complementing each other, how they find their match has been a mystery in the biological word. In a process called recombination, a damaged piece of double stranded DNA by stripping it to a single strand which looks for a complementary sequence in an intact chromosome to use a template to guide the repair. However, for over 20 years, Forget and Kowalczykowski have done experiments in their lab to see how the process happens. They did this by stretching single molecules of DNA between two tiny beads to make a dumbbell shape held in place by a laser. A protein RecA is then added to the singled strand to see how it will find its match with other DNA genomes. If there are defects in DNA repair and copying, it can cause cancer, birth defects, and other problems.
Hypothesis based because they carried out and performed an experiment to find out how one DNA strand matches up with another one.
This is important because now humans know how the DNA double helix is combined and formed so they can continue to research to find out to avoid certain mutations for the better and avoid diseases that could have once kill you.
Title of Article: Neanderthal DNA Boosts Your Immune System
Journal: Discover Magazine
Date Published: December 22, 2011
Current research has recently found that our human ancestors’ mating with Neanderthals and Denisovans (a recently discovered archaic human group) may have made them, any through evolution, modern humans as well, less susceptible to local infections. When ancient humans mated with Neanderthals and Denisovans, they picked up some of their DNA, which may have helped fortify the modern immune system.
Laurent Abi-Rached, a Stanford immunologist has stated that “breeding with our evolutionary cousins may have facilitated the spread of modern humans by preventing them from getting sick” and gave them a survival advantage as they migrated out of Africa to Europe and Asia. A team at Stanford University found that the ancient gene for HLA-A or human leukocyte antigen class 1 genes, which play a vital role in rallying the immune system to fight off bacteria and viruses and helps the body resist viruses like Epstein-Barr, is still present in half of all modern Europeans, more than 70 percent of Asians, and up to 95 percent of people in Papua New Guinea.
Scientists have been looking at bone marrow registries containing HLA genes of people from all parts of the globe. They have compared DNA from modern humans with the reconstructed genomes of Neanderthals and Denisovans and have discovered that many HLA variants from the ancient peoples are still around.
This article is an example of discovery science because in discovery science observations are made, analyzed and then tested in order to discover patterns and hopefully form a hypothesis to be formally tested. That is exactly what happened here. It was observed that modern human DNA shared many similarities with that of Neanderthals and Denisovans. Those observations were analyzed and then tested to find the cause of the similarities.
These findings help to explain where our immune system comes from and shows how ancient species played a part in how humans are today.
In an analysis of commercially available mineral waters, researchers
found evidence of estrogenic compounds leaching out of the plastic
packaging into the water. What’s also shocking, these chemicals result in an increased development of embryos in the New
Zealand mud snail. These findings, show for the first time that
substances leaching out of plastic food packaging materials act as
functional estrogens.They analyzed 20 brands of mineral water available in Germany – nine
bottled in glass, nine bottled in plastic and two bottled in composite
packaging (paperboard boxes coated with an inner plastic film). The
researchers took water samples from the bottles and tested them for the
presence of estrogenic chemicals. They then carried out a
reproduction test with the New Zealand mud snail to determine the source
and potency of the man made estrogen (xenoestrogen). The water samples from the plastic and composite packaging showed 50% more cotamination. Also, the snails in the plastic bottles produced twice the number of embryos compared to the snails in the glass bottles. These results demonstrate contamination of mineral water
with potent man-made estrogens that originate from compounds
leaching out of the plastic packaging material. The researchers conclude: “We must have identified just the tip of the
iceberg in that plastic packaging may be a major source of xenohormone
contamination of many other edibles. Our findings provide an insight
into the potential exposure to endocrine-disrupting chemicals due to
unexpected sources of contamination.”
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