Ancient DNA Sheds New Light on Africa’s Stone Age

 A study presents genome data from 3 individual, who lived in the Late Pleistocene, between 12 and 120 thousand years ago. The oldest individual was excavated in 2010 by Dr. Elizabeth Sawchuk, a bioarcheologist at the University of Alberta, and the other two individuals were excavated by Dr. Jessica Thompson, an anthropologist at Yale University. DNA extraction was less challenging than expected because the fossils were found on rocks inside a cave in Tanzania. Around 50 thousand years ago, an archeological change is seen- people started creating "trade networks". For example,  obsidian, a type of stone seen to be used in creating tools, was moved over long distances. With ancient DNA found on the stones, scientists were able to conclude the time around which humans began using and moving obsidians. It's fascinating to learn researchers were able to extract DNA from samples, given Africa's extreme weather destroys DNA. Also, this research explains how "globalization" worked then- people were moving long distances and creating families far from their birthplaces, thus changing genetic landscape.

Sickle Cell Anemia Presence in Africa

    The inspiration of this article comes from a conversation I had today with a co-worker whose ancestry descends from Nigeria. We work in an emergency room together, our experiences today is what initiated this conversation. Sickle Cell Anemia (SCA) is a homozygous recessive trait that causes an abnormality amongst red blood cells, hemoglobin is the protein in your red blood cells that is responsible for carrying oxygen. Sickle cell anemia is common in places where malaria amongst mosquitoes is prominent, natural selection promotes family pedigree who are resistant to the malaria disease. In turn, if a person is immune malaria they unfortunately carry the sickle cell trait. This immune population can either be heterozygous or homozygous recessive. Being diagnosed with sickle cell anemia brings many potential health risks including sickle cell crisis, vaso-occlusion blood clots to digits in infants, the spleen, lungs, etc. If someone has sickle cell anemia, they are immune-compromised, if their body were to come in contact with common bacterias that cause pneumonia, or common colds, without proper medical attention these bacterias can yield fatal results. The first link of my article is a video that gives insight on the pathophysiology, potential health risks, and treatment methods of sickle cell anemia. I recommend giving it a watch, as it is quite fascinating. 

    Reflecting back on the conversation with my co-worker, she began to explain some methods countries in Africa and South-East Asia use to try to mitigate the presence of this brutal disease in their countries. In her home country, it has gotten to the point where churches will not conduct a marriage unless the genotype of the parents is confirmed. If the engaged couple runs the risk of producing offspring who can suffer from SCA, the church will not conduct the marriage. While some may regard this as unethical, the prevalence of sickle cell in their country is alarming. It is estimated about 150,000 children in Nigeria have SCA, and nearly 25% of the country are heterozygous carriers of the trait. Since there is no cure for the disease, the only way to lower these numbers is to try to prevent it from being passed on. This was a very interesting topic to me, if anyone has more insight on this please leave a comment as I would like to learn more. 

Link: https://www.youtube.com/watch?v=fIIJmg_1hv0

Link: https://bmcmedethics.biomedcentral.com/articles/10.1186/s12910-019-0376-8

Link: https://www.cdc.gov/ncbddd/sicklecell/data.html 

Genetic Variations in Africa

 

        Since Africa has always had a large population there has been a theory that all human have descended from the continent. However not many individuals from Africa have been asked to participate in genetic studies to see if this is true. Zane Lombard and his colleagues studied 426 individuals from 13 African countries to see if their genomes could show any signs of variations that would help prove this theory. They ended up discovering over 3 million new variations as well as many regions of Africa that have shown signs of natural selection. Studying genomes of these individuals is important because it helps to see how past individuals migrated to different places around the world. According to this study, Zambia was a very popular migrant place. In my opinion it's quite obvious that Africa was a big pool of human descendants and hopefully more individuals from different African countries participate willingly so scientists can discover more about humanity.

https://mg.co.za/opinion/2020-11-24-africa-study-finds-three-million-new-genetic-variations/

https://www.nature.com/news/2000/001207/full/news001207-8.html#:~:text=Researchers%20led%20by%20Ulf%20Gyllensten,about%20170%2C000%20years%20ago1.

Did The Ancient Egyptians Farm Ibises?

Ibises are a bird native to Africa with a long scythe-like beak that hunt by wading through rivers. They are a sacred animal to the ancient Egyptians. Their god of writing and wisdom, Thoth, is often depicted with the head of an ibis. As an offering, the Egyptians would mummify ibises and place them in catacombs.


Scientists have discovered rooms filled floor to ceiling with these sacrifices. This raises an interesting question. Where did these birds come from? Ibises have not been native to Egypt in hundreds of years. It is unknown if they migrate in large enough flocks with high enough frequency to provide the quantity of birds required for these uncovered offerings. A theory offered instead is that they were farmed by Egyptians.

The mummification process is fantastic at preserving DNA. Scientists were able to extract mitochondrial DNA from several birds. Due to controlled breeding, you would expect to see lower levels are variance between domesticated individuals. Instead, scientists found the same levels as measured in modern day ibis wild populations. While this is not enough evidence to rule out the possibility of Egyptian farms, it suggests there might be more to the story than we currently know. I thought this was an interesting application of mitochondrial DNA. Since the mitochondrial DNA is passed down from the mother, I wonder if its possible to trace the lineage of a modern ibis to one of these mummified birds.

Links:
https://search.proquest.com/nytimes/docview/2314696925/C49933956F5741C4PQ/19?accountid=29054
https://www.smithsonianmag.com/smart-news/dna-suggests-ancient-egypts-millions-ibis-mummies-were-wild-caught-birds-180973556/ 

Association Between Diabetes and ZRANB3 Gene

The journal Nature Communications published the largest genomic study of type 2 diabetes (T2D) in sub-Saharan Africans, in which they analyzed nearly 18 million autosomal SNPs in 5,231 individuals from Nigeria, Ghana, and Kenya (Nature, 2019). Researchers found that there was a connection between diabetes and genome-wide significant locus: ZRANB3 gene. They confirmed the ZRANB3 gene, might influence weakness to the T2D in sub-Saharan African populations. They studied its effects on the zebrafish pancreas; "the pancreas is one of the key organs involved in T2D because their β-cells release insulin as a response to rising glucose in the bloodstream" (NIH, 2019).

CRISPR, a gene-editing tool was used to make the ZRANB3 gene nonfunctional in zebrafish. This is called a 'knockout'. They also reduced the expression of the ZRANB3 gene in a different sample of zebrafish. Researchers observed β-cells were reduced numbers in the developing zebrafish embryo (Nature, 2019). They concluded that when the ZRANB3 gene was inactive, pancreatic β-cells were being destroyed. They conducted a similar experiment using mice and found similar results. They proposed an excellent question on this finding: will it help to predict whether the presence of ZRANB3 in an individual with T2D require insulin early in the course of its treatment? This is significant because it could save the destruction of β-cells over time.  They also believed since ZRANB3 in T2D was discovered in African populations, the same gene might have same influence in other populations. I think this experiment was executed brilliantly considering they analyzed so much data before concluding. I think it is amazing that they want to continue the research with different pollutions and hope to find a similar association between T2D and ZRANB3 gene. 

References: 

NIH/National Human Genome Research Institute. (2019, July 19). Largest genomic study on type 2 diabetes in sub-Saharan African populations. ScienceDaily. Retrieved October 18, 2019 from www.sciencedaily.com/releases/2019/07/190719080212.htm

ZRANB3 is an African-specific type 2 diabetes locus associated with beta-cell mass and insulin response. (2019, July 19). Retrieved October 18, 2019, from https://www.nature.com/articles/s41467-019-10967-7#article-info.

Did Humans Domesticate Cats?

Dated back to ancient times, cat’s DNA showed that they domesticated themselves stated in an article on National Geographic website. Although cats now prefer to lay on the couch instead of outside their DNA shows that it hasn’t changed in thousands of years. Cats, even as wildcats, has been by a human’s side way before they became our house pets. A cat’s genes have only changed slightly in the past 9,000 years. This change appeared to be the dots and stripes on their coat of hair.

In this article, it states that researchers looked at DNA of over two hundred cats within the past 9,000 years and it showed that all the cats came from these two pedigrees; from Asia into Europe and Africa into Egypt. Both pedigrees showed that cats were not forced into being house pets, but just settled into it. Cats naturally patrolled around human's yards and killed mice and rats. They also were just attracted to humans, especially in the African lineage. 

Even though cats surprisingly attached to humans, the researchers still looked into the DNA of cats and it revealed that the DNA has not changed but the marking of its coat. When the coat of the cat was stripped, it showed that they were domesticated. This was not a definite identification of domesticated tabby cats until the 18th- 19th century.

The researchers suggested that the more we look into cats, the more we will understand the domestication process of animals. Being that cats naturally domesticated themselves, I do think further research into this animal could open up new doors or an explanation of how animals became domesticated.

A Genetic Mutation in the Khoe-San People of Africa Reduces Complications in Pregnancy

The Khoe-San people of Africa, a group that was thought to have broken off from other tribes 100,000 years ago, have been shown to have a genetic mutation in the formation of their placentas. This gene variant alters the size of placentas of mothers so that placentas are larger. This leads to healthier babies, and reduces the chances of the congenital disease pre-eclampsia, which can be fatal. It is therefore said by scientists that the Khoe-San people of Africa have developed a genetic mutation that reduces complications in pregnancy

I believe that such a genetic mutation is amazing news for the Khoe-San people. One might believe that genetic mutations can usually cause so much harm to individuals if they come to negatively affect a bodily function, however this mutation in particular is good news. This genetic mutation leads to healthier babies, and can reduce the chances of complications in pregnancy, which is particularly helpful for tribe people who may or may not have proper medical services nearby. This genetic mutation is also good news because hopefully scientists will be able to ascertain the reason behind this mutation, and in time, be able to simulate it in order to reduce pregnancy complications in the future.

A Mutation in the Ebola Virus Made Humans its Primary Target

In 2013, hell broke loose in West Africa in the form of a severe Ebola outbreak. Prior to 2013, outbreaks had never infected more than 600 people. This outbreak, however, infected over 28,000 western Africans. Other than the fact that this outbreak had reached major cities, there is another explanation for why it was so massive. The Ebola virus naturally targets fruit bats, but there is scientific evidence that the virus underwent mutations making it better suited for humans. 

A mutation was discovered in the virus's surface protein that allows it to bind to cells. This discovery was made in a study led by Harvard University's Pardis Sabeti and the University of Massachusetts's Jeremy Luban. The two geneticists tested this gene in an experiment and found that cells that were injected with this mutant gene affected humans far more easily than cells with the ancestral gene. According to Sabeti, these results "raise the possibility that this mutation contributed directly to greater transmission and thus to the severity of the outbreak." The scientists agree that there is still plenty of research to do, but something must be done before another, possibly deadlier, outbreak occurs.

The Ebola virus is a severe, often fatal disease in humans. It can be spread from animals to humans or from humans to humans. As the 2013 outbreak showed, it can spread very quickly. I agree with Sabeti and Luban in that a virus that is this deadly should be stopped before another outbreak occurs. Scientists from all around the world should do everything in their power to research this new mutation and solidify an effective treatment. 

How did we get where we are now?

Where do you think your ancestors came from? Well, it is finally concluded that even if you're not from African descent, your ancestors most likely did in fact come from Africa. We all have ancestry from people who lived in Africa 50,000-80,000 years ago!
It is well known that humans evolved in Africa roughly 200,000 years ago. But how did they disperse and colonize different lands? This is the question that three different teams of researchers began to study. In order to fully understand human history, geneticists sequenced genomes of 787 people from indigenous populations like Basques, Mayans and Cree Indians. Although early studies of DNA draw conclusions that all non-Africans are all closely related, the main question the geneticists had was how humans expanded and spread from Africa.

A single strand of hair, about a century old, gave the answer partially away. With this single strand of hair, Dr. Willerslev and his team reconstructed the genome of an Aboriginal Australian. This info was enough to give away the fact that the ancestors of Aboriginal Australians arrived about 62,000 years ago in East Asia when they descended away from other non-Africans. After all three studies were done, the teams gathered enough information from sequencing the genomes of people from different indigenous populations  to conclude that ancestors of non-Africans split off about 65,000 to 200,000 years ago! Although their is a vast time difference, they concluded that the reason for humans leaving Africa in the first place was due to the rapidly changing climate, rainfall in particular. Humans followed the tracks of the rainfall into early Eurasia where their would be better sources of food. Therefore, next time you want insight into where your early ancestors came from, keep in mind that they all came in different waves from Africa to migrate towards different lands!

How We Got Here: DNA Points to a Single Migration From Africa

The question of where humans came from has been one of the biggest in science for years. Three separate teams of geneticists from different places, all sampling different people, sequenced the genomes of 787 people from hundreds of different populations and found that all humans came from a single population from Africa between 50,000 and 80,000 years ago. The genomes were taken from a variety of people from every continent and were examined separately to finally come up with the same conclusion as to where people came from. Before now, there were very few sequenced genomes from people outside of population centers like China and Europe, but this new data with genomes from indigenous populations adds great value to our understanding of human DNA. 

The first team was Dr. Willerslev and a few colleagues who first sequenced the genome from a century-old lock of hair of an Aboriginal Australian. The results raised many questions, so the group joined David W. Lambert and the University of Oxford to obtain DNA from people from Papua New Guinea and from Aboriginal Australians to sequence. Mait Metspalu from the Estonian Biocentre sequenced genomes mostly from populations from Europe and Asia.  David Reich and his team from Harvard Medical School formed their database of genomes from people from all six inhabited continents. All coming up with the same results, the teams each established that there was an exodus from Africa 80,000 to 50,000 years ago, resulting in the populations we have today. There is also evidence of other groups migrating from Africa much earlier than 80,000 years ago, but these groups have since disappeared, having been wiped out by others who came after them who were stronger in number or in technology. 

The article discusses a study done on packaged meats in South Africa.  Geneticists took several kind of meats that were labeled as Springbok, African antelope, and ostrich when DNA testing showed that they were actually horse, giraffe, and kangaroo.  146 samples of meat were tested and over 100 were improperly labeled.  All beef was correctly labeled.  Similar results were found in other countries.  The results will be used to help enforce food regulations.    

I found this article interesting because I'm astounded by how poorly food is regulated in foreign countries.  It makes me feel blessed to live in a country where such a thing is highly regulated.  I never thought geneticists would have to do such a thing.    

Here's the article  

'Gene drive' mosquitoes engineered to fight malaria

         


         Malaria is the number four leading cause of death in Africa.  Accounting for 6% of deaths in sub-saharan Africa. Scientists however may have recently cracked the case to wipe out the disease in some regions for good.  Malaria is spread almost entirely through mosquitoes.  In Africa the mosquitoes that spread Malaria are infected with a parasite of the Plasmodium genus.  Every time a mosquito bites a human it injects some of the parasite into their blood stream.  Scientist have been studying the mosquito's genome intensely to discover a way to fight Malaria.
           The idea was that if scientists could engineer the mosquito's genome so that it would be resistant to the parasite than the mosquito would no longer spread the disease.  However the problem was that it is nearly impossible to genetically engineer a whole wild population of mosquitos with the same gene.
            Insert the concept of "gene drive".  Gene drive basically is a way to alter the inheritance pattern to favor the inheritance of one particular gene.  This would allow the genetically engineered mosquitos to pass on its resistant genes to all of its offspring rather than just half.  Anthony James a molecular biologist at the University of California Irvine wrote a paper suggesting that this method of gene drive could affectively wipe out malaria.  He recently was contacted by other biologists who successfully engineered a gene drive in fruit flies.  James used their same method a gene editing system called CRSPR-Cas9 in mosquitos and found that 99% of the offspring received the resistant gene.
           In my opinion I am a bit skeptical by engineering entire populations of mosquitos, because we do not know any other side affects of the gene drive or transgenic material in the mosquito.  However I am amazed that there is a method that scientist have come of with that has the capability to completely wipe out a disease in Malaria that has plagued third world countries for centuries.

Original Post

CRSPR-Cas9

Guinea, Last Nation With Ebola, May Soon Be Declared Free of Virus

       
   
           Citizens of Guinea anxiously wait on pins and needles as they loom to expect the declaration that their country is finally Ebola free.  They are the last nation still suffering from the virus.  They have to wait about 42 days (The amount of time for two incubation periods of the disease to take place) as many people are still being monitored.  The final patient in the world in an active treatment center was a 3-week old girl, Nubia Soumah just recently tested negative twice.

          Nubia will also be the first infant of a mother that had the disease to survive.  The virus has crippled the economy and regular day life of this country, so the citizens of Guinea are waiting patiently so that they can truly start to repair the damage the virus has done.

        What stood out to me in this article was the work done by an organization known as Doctors Without Borders.  Doctors without Borders is a non profit organization that medical assistance to third world countries.  As a biology major it is something truly inspiring to see these doctors going overseas and treating Ebola patients.  I was always amazed by the work that they do.

         Overall with Guinea nearly Ebola free it just shows how advanced our vaccination technology is present day with a disease that was very frightening and now is almost completely gone.


Original Post

Doctor's without Borders

The African Genome Variation Project

Through the African Genome Variation Project, scientists have completed a comprehensive study of genetic diversity in Sub-Saharan Africa. This project analyzed the DNA of 1,800 people living across Africa for genetic risk factors for disease. Most of these types of projects and research have been done in Europe while little has been known about Africa, the most genetically diverse region in the world.

http://25.media.tumblr.com/tumblr_loa5m3vYuO1qbh26io1_1280.jpg

The researchers were curious to understand if there was underlying genetic susceptibility that caused some diseases. They were not able to get the information they needed since Africa has a large variation in genomes and has barely been genetically studied. This lead to UK and US researchers collecting genetic material from people in Africa and the researchers found some different variations with region. For example, South African people are less likely to carry a genetic mutation that protects from malaria. Also Africans are more likely to have a greater risk of high blood pressure compared to Europeans.
The most surprising thing that researchers learned was that Africans are not as diverse as researchers expected. This is a good thing because it means large scale trials can be used to understand disease susceptibility. This project will also be able to help scientists more clearly understand diseases and why people are more likely to get certain diseases. Scientists will also be able to learn about more ancient migration patterns in early humans.
I found it surprising that not much genetic information has been gathered in Africa. There should be projects like this all around the world to help understand more about humans. It will also be extremely interesting if links are found been certain genes and diseases since everyone was panicking over ebola 2 weeks ago. This type of project will be helpful in the medical and genetic field.

Article: http://www.bbc.com/news/science-environment-30318291

Immunity to EBOLA?

On November 10, 2014, the New York Times released an article discussing the recent findings from researchers that claim that the survivors of Ebola have certain antibodies that can help current victims with overcoming the horrible disease. This immunity is only present in the current outbreak in West Africa called, Ebola Zaire. For many years, scientists have found that some Africans have a natural genetic disposition to fight off Ebola. They can be surrounded by the disease but not display any of the symptoms. In the year 2000, a team of French scientists conducted a research study in which they took thousands of blood samples from various villages across Gabon to test whether or not the members of these villages possessed these antibodies. They found that 15% of the population did; of the 15%, 3% were near the coast and 34% were near the jungles of Congo. Scientists however, still are unaware of what genes are responsible for this immunity and how strong or weak these antibodies are. There was evidence of people with very low and high levels of antibodies. Although the source of these antibodies are unknown, researchers suggest that the African population could have come in contact with the virus by eating monkeys or fruit bats. Because they are natural harbors of the virus, if eaten, a small amount of the virus can enter the blood stream enough to result in immunity. Although researchers would like to believe that these antibodies could greatly improve the conditions for current victims of Ebola, they do not have solid evidence that it is effective.

This article was a very interesting read. With the recent uproar about the spreading of Ebola, it is great to hear that scientists may have a breakthrough in its prevention. One of the questions that arose while reading this article was how scientists are going to go about testing whether or not their hypothesis is true. I recently watched a video that covered the first outbreak of Ebola in Africa which discussed this very topic of immunity. It showed that the western doctors decided to test their antibody theory by injecting people who did not have Ebola with the Ebola virus, and then injecting them with the blood of a survivor to see if the antibodies would fight off the disease. I found this to be a very inhumane and unethical form of medical practice. Although I do not think scientists would resort to such practices, it is interesting to see how they will go about it. In my opinion, it would be much more logical to test the theory out on someone who is already affected by the disease, as long as the blood types match.

Artice: http://well.blogs.nytimes.com/2014/11/10/ask-well-immune-to-ebola/?module=Search&mabReward=relbias%3Ar%2C%7B%222%22%3A%22RI%3A16%22%7D&_r=0

Related Article: http://www.theguardian.com/society/2014/sep/04/ebola-experts-antibodies-survivors-blood-potential-cure

The Lost Identity of Man's Best Friend

We believe that the origin of Earth was caused by the Big Bang 13.7 billion years ago, but what can we say about the origin of dogs?

Comparing the two, the origin of dogs may seem minuscule and unimportant but just how much do we know about our best friend? Some people agreed on the fact dogs came from wolves, aside that we only know dogs appeared around 15,000 to 100,000 years ago somewhere in Asia or Africa.

According to Dr. Greger Larson at University of Durham, England, it is currently improbable to trace when and where dogs originated from the DNA of modern dogs. Larson and twenty other authors have been working on a paper about the origins of dog domestication. Currently the team has analyzed 49,024 locations on dog DNA; working with 1,375 DNA samples from 121 breed, and 19 wolves.So far they have only been successful tracing back to about a hundred years.

Larson and his colleagues concluded on how modern dog breeding is making it more difficult to locate when or where dogs were first domesticated. In fact, dog breeding had been so mixed, that the genetic history for dogs became very obscured; with the exception of basenji, shar-pei, Saluki, Akita, Finnish spitz, and Eurasier bring slightly less mixed.

What Larson and his team found out was that, dogs that are most genetically distinct were not from the places where the oldest dog fossil was found. Larson expected if these breeds were closer genetically to the first domesticated dogs, they would be geographically closer to sites of early dog fossils or ancient dog breeds. However, their studies shows the more genetically distinct dogs had been geographically isolated quite recent in the history of domestication. For instance, dingoes, basenjis, and New Guinea singing dogs came from southeast Asia and southern Africa about 3,500 and 1,400 years ago.

Larson concluded that there is still hope to learn about the origin of dogs. People have burying their dogs for a long amount of history, thus somewhere, there really is a fossil of an ancient dog--we just have to find it.

I think dog breeding is one of the things we, as humans take for granted. We decide on the breed that we want for our own purposes, not knowing the consequences of our selfishness. In order to create a companion to cuddle and be dog show material--we have made our best friend lost his identity. Everyone kept saying how much they love their dogs, but just how much do we know about their history?

Original article: http://www.nytimes.com/2012/05/22/science/dogs-genetic-roots-remain-obscure.html?_r=0

Related article: http://www.npr.org/2013/07/10/200498354/barking-up-the-family-tree-american-dogs-have-surprising-genetic-roots

Scientists crack genetic code of tsetse fly

 

    According to MediLexicon International's article, A 10-year project involving more than 140 scientists around the world has resulted in the successful sequencing of the genetic code of the tsetse fly "Glossina morsitans". The fly is the sole carrier of African sleeping sickness or trypanosomiasis, a disease that threatens millions of people across sub-Saharan Africa and devastates livestock. An estimated 70 million people in across sub-Saharan Africa are at risk for sleeping sickness, which occurs in two stages.

 



    The first stage of infection causes fever, headaches, aching joints and itching. The second stage, when the parasite crosses the blood-brain barrier, causes confusion, poor co-ordination and the sleep problems that give the disease its name. Without treatment, African sleeping sickness is fatal. Also, diagnosis and treatment are difficult, and require specially trained staff to administer them. And while drugs exist, they are expensive and have many undesirable side effects. In livestock, trypanosome infection causes anemia and weight loss, which can lead to death. The result is billions of dollars of livestock lost every year. Although the infection is not found in the United States, historically, it has been a serious public health problem in some regions of sub-Saharan Africa (Uganda, the Democratic Republic of the Congo and Sudan). By unraveling the genetic code of the tsetse fly, researchers have essentially produced a "parts list" of the organism. The blueprint contains codes for all the 12,000 genes that control protein activity in the fly. Giving scientists access to the blueprint is expected to speed up research into the fly's unusual biology and lead to new methods and strategies for controlling the fly.

 

 

     It is interesting to read how the tsetse fly genome comprises around 366 million letters of code, which is about one tenth of the size of the human genome. Its also unique in that unlike other flies the tsetse only gives birth to few offspring at a time, and each fly only yields a small amount of genetic material. Tsetse fly is highly unusual among insects in that they have developed unique partnerships with bacteria for several aspects of their biology, and they give birth to live young that have developed to a large size by feeding on specialised glands in the mother. It's exdrodinary how sleepiness sickness is caused by microscopic parasites of the species Trypanosoma brucei. It is hoped the genome map of the tsetse fly will help scientists understand more about evolutionary biology.

 

For more information on the parasites that cause sleeping sickness via flies, you can vist http://www.doctorswithoutborders.org/our-work/medical-issues/sleeping-sickness

Mutations in P. vivax could make millions susceptible

P.vivax infection in Duffy positive individuals, and resistance in Duffy negative individuals 

100 million cases of malaria a year are caused by the parasite Plasmodium vivax. Peter Zimmerman of Case Western Reserve School of Medicine and David Serre of Genomic Medicine Institute at Lerner have identified mutations in P. vivax that could cause susceptibility in tens of millions of Africans previously thought to be resistant. The mutations involve a mechanism that allows the parasite to infect red blood cells and an invasion that may allow for more complex invasion. Previously, it was believed that the Duffy binding protein on P. vivax attached to the Duffy receptor on the red blood cell and that those without the receptor (Duffy negative) were resistant. Yet, in the past decade there has been an increase in P. vivax infections in Duffy negative individuals. A study from 2010 found that 10% of those with clinical malaria were infected by P. vivax and were Duffy negative. 2.5 billion people are estimated to be at risk. The malaria is deemed benign but is chronic, hiding in the liver and causing reoccurring nausea, headaches, and fever that can leave the infected unable to work. Further, it contributes to death by deteriorating the immune system. Of 189 samples for Madagascar, half possess duplicate Duffy binding protein. Less than 10% of the samples from Sudan and Cambodia possessed the mutation. The recent mutation may be spreading though travelers in Madagascar.  The fear is that the mutation will allow P. vivax to travel into Africa.

Field study will begin in 2014 to determine if it is evolving and to learn the mutation’s functions.  Serre, Zimmerman and their team will study the blood samples of 1,500 individuals from Madagascar. Research will also be done on samples from Africa, South America, and Asia. The goal is to create a vaccine, possibly focusing on the binding mechanisms of P. vivax.

I found this article to be very interesting and of much significance. As stated in the secondary article, malaria is one of the “big three diseases” and three million are newly infected with P. vivax specifically annually. The risk of the spread of P. vivax to the rest of Africa could be detrimental. Thus, the study is crucial to the well being of Africa. I find it fascinating that the researchers are using the problem to find a solution, by looking at the mechanism of infection as a target. I find the power of science to consistently use a problem as a solution incredible! I am curious to see the results of the study that will be carried out in 2014 and hope a solution can be found.

Primary Article: http://www.sciencedaily.com/releases/2013/11/131115094906.htm

Secondary Post: http://www.sciencedaily.com/releases/2010/03/100315162043.htm

The Bitter Taste Gene

    We all perceive the tastes of certain foods differently. You may find specific food disgusting, while your brother or sister finds it delicious (brussel sprouts for instance). Researchers from the University of Pennsylvania have recently done a new study, finding a genetic mutation that makes certain people more sensitive to the taste of a bitter compound, which could have been very beneficial for certain humans in Africa. Because of this, the gene mutation has been passed from generation to generation due to the fact that Africa is the origin of all modern humans. This study represents the first time that the bitter-sensitivity gene, known as TAS2R16, has been studied in such a large set of ethnically diverse African populations. The new study was built on previous research that looked at the evolutionary history of the TAS2R16 gene, which allows humans to sense the bitter taste. This recent study examined the TAS2R16 gene that codes for a receptor that attaches to salicin, a naturally found bitter compound (in willow bark and source of aspirin). Salicin is an anti-inflammatory and can be found in many nuts, fruits, and vegetables.
     This new study sampled DNA from about 600 people in 74 populations across Africa with many different kinds of lifestyles. The researchers then sequenced the TAS2R16 gene in all of the Africans as well as 94 non-Africans for comparison. They were able to identify 15 variants of the gene, most only found in Africa. About 300 of the Africans also performed a taste test of different concentrations of salicin, expressing when they could detect the "bitter" taste. This taste test showed that the TAS2R16 gene caused a gain of taste function. When the researchers matched the individuals' genetic profiles with their taste testing performance, they discovered that there was a strong connection between one of the variants and an increased sensitivity to salicin. Cellular analysis also showed that the individuals with this particular genetic variant had almost twice as many receptors for salicin than those with other forms of the TAS2R16 gene. The high-sensitivity variant was most common in people from East Africa (not West or Central Africa), which indicates an evolutionary change. Non-Africans were found to only have the high-sensitivity version of the gene. For the future researchers hope this study can start giving us clues as to what we should look at in terms of the bio medical and physiological significance of these genes.

I chose this article because I find it interesting how some people can like certain tastes while others do not. This helped me understand where exactly the bitter tasting gene comes from and how it works. This was very informative and I think it will help researchers with future studies of taste buds.





Article: http://www.redorbit.com/news/science/1113000905/genetic-mutation-bitter-taste-human-evolution-111213/

Link: https://www.23andme.com/health/Bitter-Taste-Perception/

Scientists use genetics and climate reconstruction to track global spread of modern humans out of Africa

Scientists have developed a model to predict the routes taken by modern humans, H. sapiens, out of Africa 100 thousand years ago.  This model was published on September 17^th in PNAS (Proceedings of National Academy of Sciences).  “By combining extensive genetic information with climate and vegetation models, we were able to build the most detailed reconstruction of human history so far,” stated Dr. Anders Eriksson, the lead author of the paper and a professor at the University of Cambridge.  Using this reconstruction the scientists were able to determine the best routes for the early humans to take out of Africa.



During their study, the scientists considered climate change, food availability, birthrates, and many other factors that would influence a large scale movement of populations.  They determined that food availability, which was scarce in Northern Africa, prevented most movement out of the continent until a break in the cold weather came approximately 70-55 thousand years ago.  Most modern humans then traveled out of Africa via the Bab-el-Mandeb strait into the Arabian Peninsula.

The research presented by the scientists is supported by the fossil record, which was not actually used to generate the models.  There is, however, a major exception of Europe.  The scientists’ model predicts the presence of H. sapiens in Europe 10 thousand years prior to their appearance in the fossil record.  This discrepancy is most likely due to competition with Neanderthals at the time, which was not included in the models. The ability for scientists to combine all influencing factors to create a movement model for early humans is incredible, especially since they did not use the actual fossil record when creating their model.  It will be interesting to see if they will be able to find evidence of interactions with Neanderthals to back up their theory on delayed expansion into Europe.  I was expecting more information regarding the genetics portion of the study than what was actually in the article.