Category Archives: Human Genetics

When it comes to attraction, the allure can begin even before she sets eyes on you. There seems to be something about the way youher dinnersmells from afar that makes you a desired target. While you are chatting with friends or overseeing the barbecue, that mosquito will go on the hunt and make you her next blood meal. But what makes you so attractive to tiny ankle biters?

This month a group of British researchers is launching a new investigation into the role of human genetics in this process. They are planning to collect smelly socks from 200 sets of identical and nonidentical twins, place the footwear in a wind tunnel with the bugs and see what happens next. The owners of the socks, the scientists hope, may naturally produce attractive or repellant chemicals that could become the basis for future mosquito control efforts. The researchers expect that studying the popularity of the garments the skeeters hone in onand analyzing both the odor compounds in them and the genetics of their ownerscould help.The study, which will include 100 twins each from the U.K. and from the Gambia, will start recruiting volunteers in the coming weeks.

We know very little about the genetics of what makes us attractive to mosquitoes, says James Logan, a medical entomologist at the London School of Hygiene and Tropical Medicine who is leading the work. Earlier studies suggest visual, olfactory and thermal (body heat) cues all help drive mosquito attraction. We hope this study will give us more insights into the mechanisms that help change our body odors to make us more or less attractive to mosquitos, he says. If we can identify important genes, perhaps we could develop a pill or medication that would allow the body to produce natural repellents to keep mosquitoes away. The findings, he adds, could also help epidemiologists improve their models for how vulnerable certain populations may be to disease-carrying mosquitoes.

Already scientists know there are differences among us that contribute to why some of us get bitten more. Those of us who exhale more carbon dioxide seem to be a natural beacon for mosquitoes, in particular. Researchers have also found a correlation with body size, with taller or larger people tending to attract more bitesperhaps because of their carbon dioxide output or body surface area. There is also some evidence women who are pregnant or at certain phases of the menstrual cycle are more attractive to mosquitoes. Other work has found that people infected with malaria are more attractive to malaria-carrying mosquitoes during their transmissible stage of infection.

But what of our individual genetics? Two years ago Logans team published a small study looking at 18 sets of identical twins and 19 sets of nonidentical twins and their attractiveness to mosquitoes. They found that identical twins were more similar in their desirability to the blood-sucking insects than the nonidentical twins. Because earlier work had found that identical twins smell more alike than nonidentical twins, the British researchers surmised genes may play a role in this mosquito attractiveness.

This new study aims to nail down some more concrete conclusions with its larger sample size and add another population into the mix. (Most research in this area has focused on European Caucasians whereas this study will also include twins from the Gambia). There are other differences that set this apart from their earlier work, too: The 2015 study had tested attractiveness among Aedes mosquitoesthose that carry dengue and Zikawhereas this study will test attractiveness among Anopheles mosquitoes, a species that can transmit malaria. The team suspects the different species will be attracted to the same volatile compounds in human odor but wants to explore this further.

This is novel work and its a good step. It will tell us if there are genetic differences or not but it wont be a complete answer about mosquito attraction because other factors like diet, wind, time of day and mosquito species can all influence that, says Zainulabeuddin Syed, a professor of biological sciences at the University of Notre Dame who studies the smell-influenced behavior and movement of insects and is not involved in the Logan project. Syeds work has found that people of various ethnic groups all seem to produce four major volatile compounds (although at varying levels) and there are some early hints that one compound in particular, called nonanal, may be particularly attractive, at least among certain species of mosquitoes.

Exactly what genes contribute to producing compounds that could possibly interest mosquitoes remains a vast unknown. Scientists that study human odors and genetics have previously suggested scent cues associated with genetics are likely controlled via the major histocompatibility complex (MHC) genes. Those genes appear to play a role in odor production and also in mammals mating choicesbecause humans and mice alike appear to prefer mates that smell less similar to themselves, which scientists have theorized may be a natural control against inbreeding. As a result, Logans team may target those odor-linked genes, but he says they are looking at all the options. In the next couple of years, he says, they hope to have some early answers. For now, and likely for many years to come, we can only slather on some bug repellant and hope for the best.

Read the original:
Are You a Magnet for Mosquitoes? - Scientific American

It is a 2001 deja vu moment in 2017, as we saw the 1901 deja vu moment in 2001.

Michael Bamshad Does A Herbert Risley

In 2001, population geneticist Michael Bamshad of the Institute of Human Genetics, University of Utah, studied the genetic makeup of caste groups from Visakhapatnam district in Andhra Pradesh and compared them with various castes and regional groups of India as well as those in Africa, Asia and Europe. Then in his paper, he announced how the 'genetic distances' between castes correlated with social rank. The 'upper castes' were 'significantly more similar to Europeans' than the 'lower castes', he concluded.

Exactly a century before Bamshad, there was Sir Herbert Risley, commissioner for the 1901 census of India and honorary director of the Ethnological Survey of the Indian Empire, who had applied the nasal index to the castes. He had proved how Indian castes belonged to several racial categories from dark skinned, snubbed nose Dravidians to fair skinned Aryans with pronounced proboscis.

Doubts were raised from the Indian side, when Swami Vivekanandas brother B N Dutta challenged Risleys notion that higher castes had European noses. He simply used more data than Risley.

Later, in a detailed work on the origins of untouchability, Dr B R Ambedkar, the chief architect of the Constitution of India, questioned the methodology and conclusions of Western ethnography. Considering the colonial thesis that the so-called untouchables belonged to a different race from the caste Hindus, Dr Ambedkar made a profound statement. Even if one were to consider anthropometry as a science by which the race of a person could be established, he said, the data obtained "disprove that scheduled communities belonged to a race different from the rest of Hindu communities. The measurements prove that the Brahmin and the Untouchables belong to the same race."

So, did Bamshad in 2001, with Single Nucleotide Polymorphism in the place of nasal index, prove Risleys colonial ethnographic project of 1901 right and Dr Ambedkar wrong?

Interestingly, the story was immediately grabbed by popular science magazines as well as local media. Popular Tamil newspaper Dinamani wrote an article approvingly quoting Bamshads paper as Aryan invasion/migration theory being finally proved by science.

UK-based popular science magazine New Scientist presented the Bamshad paper with the sensational heading 'Written in blood'. It then quoted a pro-missionary scholar Robert Hardgrave as saying that there are 'some historical and archeological evidence' that the "Aryans came in, they intermarried with indigenous people and also absorbed many of them into their social system of ranking".

The Times of India newspaper reported the study with the prominent heading in its international section: 'Upper caste Indian male more European, says study'.

Frontline, the magazine from the Left-leaning The Hindu family of publications, in reporting the Bamshad paper announced sensationally: "New genetic evidence for the origins of castes indicates that the upper castes are more European than Asian. It took a potshot at 'strident nationalism' in the form of 'Hindutva' ideology, which rejects the premise that Aryans were outsiders." While conceding that the archeological evidence of marauding or migrating Aryans was wanting, the article declared "modern population genetics, based on analyses of the variations in the DNA in population sets, has tools" that could provide "a more authoritative answer". And that answer was that the Y-chromosomes of the 'upper caste' men had markers closer to Eastern Europeans than to the Asians.

One lone media voice that questioned the study was India Today. Labelling the Bamshad study 'controversial', an article in the publication drew parallel with the pseudoscientific racial study of Risley a century ago. The magazine quoted the famous archeologist Dilip Chakravarti, questioning the terminology used by the papers. The article cautioned readers against taking the paper as the final say on the matter. Soon, the Bamshad study was followed by another study in 2004. A team of six scientists, including Richard Cordaux of Max Planck Institute for Evolutionary Anthropology, studying the origin of the 'Hindu caste system' concluded that 'paternal lineages of Indian caste groups are primarily descended from Indo-European speakers who migrated from central Asia 3,500 years ago'.

Subsequent Studies Reject The Authoritative Answer

In 2003, Dr Toomas Kivisild and 17 other scientists published a paper, which studied both tribal and 'caste' populations. The paper reported that the "Haplogroup R1a, previously associated with the putative Indo-Aryan invasion, was found at its highest frequency in Punjab but also at a relatively high frequency (26 per cent) in the Chenchu tribe". This suggested that southern and western Asia might be the source of this haplogroup.

This study did not receive the media spotlight that Bamshad paper received. However, it did prove to be a turning point. Dr Gyaneshwer Chaubey, of Estonian Biocenter, who is an expert in the field of biological anthropology and evolutionary biology, says, "the paper is still true and that is the one which has enlightened me to move to population genetics from Drosophila genetics!" Dr Chaubey since then has been at the forefront of research work related to the peopling of South Asia and is co-author of almost all the important papers dealing with the subject.

Then in 2006, a major genetic study of the Indian population was taken up by a team of 12 scientists. The study produced results that contradicted the 2001 study of Bamshad et al. However, this too did not receive the media attention it deserved. The paper had concluded:

Read more:
Here We Go Again: Why They Are Wrong About The Aryan Migration Debate This Time As Well - Swarajya

Clay Siegall, CEO, Seattle Genetics

In the wake of Seattle Genetics announcement that a disturbing tilt in deaths pointed to a likely safety problem for its late-stage cancer drug vadastuximab talirine (SGN-CD33A), the FDA has stepped in to yank the IND and officially put any human testing on hold.

The biotech $SGEN reported the FDAs move in a filing with the SEC this morning.

Seattle Genetics had already hit the brakes on its R&D work on the drug three days ago, scrapping the Phase III for acute myeloid leukemia and ordering a halt to any other testing until they can get a better read on the situation. It will also have to convince regulators that the drug is safe for testing after the FDA had lifted its first clinical hold on the drug just three months ago. That first hold on its early-stage work came after four patients died.

Those deaths were linked to liver toxicity, a classic red flag on safety. But this time one of the few clues provided by Seattle Genetics is that liver toxicity did not appear to be behind the disturbing rate of deaths investigators were seeing.

Back in March the biotech reported that it was getting restarted on the clinical work after it came up with revised eligibility criteria and stopping rules for veno-occlusive disease.The FDA agreed to lift the hold only two months after it was dropped on Seattle Genetics.

With its big Immunomedics deal axed by activists and its lead clinical drug in big trouble, Seattle Genetics CEO Clay Siegall will come under heavier pressure to diversify beyond Adcetris.

News reports for those who discover, develop, and market drugs. Join 16,000+ biopharma pros who read Endpoints News articles by email every day. Free subscription.

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FDA padlocks any new human tests on Seattle Genetics' cancer drug in the wake of more deaths - Endpoints News

An international non-profit organization has raised concerns about Chinas mass collection of DNA data from its citizens.

Asian Scientist Newsroom | June 23, 2017 | Top News

AsianScientist (Jun. 23, 2017) - China holds the largest searchable DNA database in the world; genetic information from over 40 million individuals that is ostensibly to be used in the fight against crime. However, the way in which these data are collected and the protection given to providers leave much to be desired, according to the European Society of Human Genetics (ESHG).

There is growing evidence that DNA is being collected from ordinary individuals who have not been convicted nor even suspected of a crime, and that this collection is compulsory. Police have also taken samples from groups that are already under increased government surveillance, such as dissidents, migrant workers and ethnic minorities, said Professor Martina Cornel, chair of the ESHG Public and Professional Policy Committee.

Because police powers in China are so extensive and people have little right to privacy, they are unable to refuse to provide such personal data.

People who have been compelled to provide DNA have reported their experiences via social media. Collections are made by police at their workplaces, homes and schools, with no prior notice and without the presentation of any official document justifying the taking of samples. Some people have also been asked to provide DNA samples when applying for documents such as residency permits from the police.

In Xinjiang, a province that is home to around ten million Muslim Uyghurs, an ethnic group already suffering state repression, all passport applicants are now required to provide DNA samples, irrespective of whether or not they are suspects in a criminal case.

This is in total contradiction to all existing regulations and safeguards concerning the collection of DNA samples from individuals, said Cornel.

We know that such databases can be used for government surveillance, including identification of relatives. Collection of DNA without the subjects full, informed consent can only be justified in extremely limited circumstances, for example in order to solve a very serious crime. A collection of samples from individuals where no such consent has been given has been ruled illegal by many international bodies, and the very existence of such a database is dangerous.

ESHG calls on the Chinese government to follow in the footsteps of all responsible authorities and ensure that human DNA is collected only from individuals suspected of having committed serious crimes, and that informed consent is given whenever possible.

Source: European Society of Human Genetics; Photo: Shutterstock. Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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Does China's Mass Collection Of DNA Violate The Right To Privacy? - Asian Scientist Magazine

Theme: Novel Approaches to Unraveling the Human Genome and Genetic Disorders

Human Genetics Congress 2017 welcomes you to attend the 3rd World Congress on Human Genetics & Genetic Disorders which is going to be held at Toronto, Canada during October 20-21, 2017 with the theme of Novel Approaches to Unraveling the Human Genome and Genetic Disorders We cordially invite all the participants interested in sharing their knowledge and research in the arena of study of organisms and their relationship with Life Science.

Human Genetics do have boundaries, but determining where one Genetics starts and another begins can often be a challenge. We anticipate more than 300 participants around the globe with thought provoking keynote lectures, oral and poster presentations. The attending delegates include Editorial Board Members of related journals. The scope of Human Genetic-2017 is to bring the advancements in the field of science of all the relations of Genetics, all organisms in Life Science.

Follow us: https://www.facebook.com/Human-Genetics-Congress-2017-1427724823932698/

LinkedIn: https://www.linkedin.com/in/preeyanca-williams-5a3546143/

Email 1: humangeneticscongress@geneticconferences.com

Email 2: humangenetics@conferencescanada.org

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3rd World Congress on Human Genetics & Genetic Disorders - Technology Networks

FINDINGS

A new study by scientists at UCLA found that when mice eat a high-fat diet, the cells in their small intestines respond the same way they do to a viral infection, turning up production of certain immune molecules and causing inflammation throughout the body. The scientists also found that feeding the mice tomatoes containing a protein similar to that in HDL, or good cholesterol, along with the generic cholesterol drug Ezetimibe, reversed the inflammation.

The results could lead to new types of drugs, targeting the intestinal cells, to reduce peoples risk of heart attacks and strokes, or to treat other conditions linked to inflammation, including cancer and inflammatory bowel disease.

Researchers already knew that prolonged obesity can cause inflammation of the liver and fat tissues, and that this inflammation contributes to the development of diabetes and heart disease. Studies have also shown that higher levels of high-density lipoprotein, or HDL, cholesterol, reduces a persons risk of heart disease.

The UCLA research team, led by Alan Fogelman, chair of the department of medicine at the David Geffen School of Medicine at UCLA,previously developed genetically engineered tomatoes that contained 6F, a protein resembling the main protein in high-density lipoprotein. In early experiments on 6F, they found that the compound was active in the small intestines of mice, and that it reduced inflammation. But exactly how it did this was unclear.

The scientists fed either a standard chow or a high-fat, high-cholesterol Western diet to mice that were especially prone to developing clogged arteries. They also treated some of the mice with either 6F, in the form of a tomato concentrate containing the protein, Ezetimibe, or both. After two weeks, cells from the small intestines of the mice were collected and blood samples were taken. The researchers measured cholesterol levels as well as the levels of inflammatory and immune molecules in both the intestines and throughout the body.

The findings shed light on the molecular details of how high-fat diets cause inflammation in the body, by making the intestines activate the pathway normally triggered by a virus. This suggests that blocking this immune reaction as 6F and Ezetimibe do may treat inflammatory diseases and decrease peoples risk of heart attack and stroke.

The authors of the study are all faculty and researchers at UCLA, affiliated with the Department of Medicine; Department of Molecular and Medical Pharmacology; Department of Human Genetics; Department of Microbiology, Immunology & Molecular Genetics; Department of Pathology and Laboratory Medicine; Department of Obstetrics and Gynecology; Semel Institute for Neuroscience and Human Behavior; and Department of Molecular, Cell and Developmental Biology. The first author is Pallavi Mukherjee; Fogelman is the senior author.

The studywas published June 7, 2017, in the Journal of Lipid Research.

The study was funded by the United States Public Health Service (2P01 HL-30568) and the Castera, Laubisch, and Milt Grey funds at UCLA.

Alan Fogelman, Mohamad Navab and Srinivasa Reddy are principals in Bruin Pharma, which is working to commercialize apoA-I mimetics, including the 6F peptide studied in this paper; Fogelman is additionally an officer of the company.

Read more:
High-fat diet leads to same intestinal inflammation as a virus - UCLA Newsroom

An international team led by researchers from UCLA and Massachusetts General Hospital has identified the first definitive genes associated with Tourette syndrome, giving scientists a long-sought foothold on the biology of the disease.

The report in the June 21 issue of Neuron describes the discovery of rare mutations either deletions or duplications of genetic material in two neurodevelopmental genes, NRXN1 and CNTN6, in people with Tourette syndrome, a disorder characterized by multiple chronic, involuntary motor and vocal tics.

This is a first, key step in understanding the role of these genes in the disease process and ultimately in pointing the field toward possible therapeutic strategies, said Dr. Giovanni Coppola, a professor of psychiatry and neurology at UCLAs Semel Institute for Neuroscience and Human Behavior, and the studys co-senior author. All of us in the field have been trying to understand which genes increase the risk of disease.

Theres no cure for Tourette syndrome, and no one medication that is helpful to all people with Tourette syndrome or suppresses all symptoms.

Previous research has shown Tourette syndrome has a clear genetic component. But genetic risk appears to be very complex, possibly involving different genes in different individuals. Several small studies have identified genes that appear to contribute to Tourette syndrome risk, Coppola said, but none of them met the statistical threshold of significance.

For this study, researchers analyzed data collected by the Tourette Syndrome Association International Consortium for Genetics and the Gilles de la Tourette Syndrome GWAS (genome-wide association studies) Replication Initiative from more than 2,400 people with Tourette syndrome.

Of those people, only two dozen shared rare genetic mutations onNRXN1, which has a role in the development of synapses that transmit signals between neurons, orCNTN6, which is important in the development of neuronal connections involved in movement control.

To test whether these findings were specific to Tourette syndrome and not coincidence, researchers looked for the mutations in 4,100 people without Tourette syndrome. They found that the mutations were vastly predominant in people with Tourette syndrome.

The finding is also relevant to other neuropsychiatric disorders. More than 85 percent of people with Tourette syndrome have attention deficit hyperactivity disorder or obsessive-compulsive disorder, or elevated risk for mood, anxiety, major depressive and autism spectrum disorders. Next, scientists plan to study cells from people with these rare genetic variantsto understand more precisely how they are involved in these diseases.

Tourette syndrome has long been considered a model disorder to study the parts of the brain that function at the intersection of our traditional concepts of neurology and psychiatry, said Dr. Jeremiah Scharf of the psychiatric and neurodevelopmental genetics unit in the Massachusetts General Hospital departments of psychiatry and neurology and co-senior author. Identifying additional genes will give us additional points on the map to let us focus in on exactly which cells in the brain are not functioning correctly at which specific times.

John Miller, president and CEO of the Tourette Association of America, which provided support for the study, called the identification of the two genes an enormous step forward. We congratulate our colleagues on this important discovery and on the real progress it means for individuals with Tourette.

The studys first author is Alden Huang, a doctoral student in the UCLA bioinformatics program. Additional co-senior authors of the study are Dr. Carol Mathews of the University of Florida and Peristera Paschou of Purdue University. Other support for the study came from the National Institute of Neurologic Disorders and Stroke grants U01 NS040024, K02 NS085048, P30 NS062691 (Informatics Center for Neurogenetics and Neurogenomics, ICNN) and NS016648; National Institute of Mental Health grants K23 MH085057 and MH096767; and American Recovery and Reinvestment Act grant NS040024-07S.

Coppola said that he is especially grateful to patients who agreed to be part of the study. As a neurologist in Italy, where he trained, people volunteering for genetic studies would ask him, What is the possible outcome of this? and he would say, Most likely, nothing.

Now, with this studys results, Coppola can point to a success story: Next time your doctor asks you to give your DNA for testing, and tells you chances are dim for the result being relevant, keep in mind sometimes it works. And the more people enrolled, the better it works.

See original here:
Rare genetic variants found to increase risk for Tourette syndrome - UCLA Newsroom

An artists impression of Homo floresiensis.

Katrina Kenny

Just when we thought we were getting a firm grip on the place of the diminutive early human Homo floresiensis, better known as the hobbit, in our evolutionary family tree, new research keeps alive at least part of a long-held theory about the one-metre-tall hominid being a dwarf descendant of Homo erectus, the first hominid believed to have left Africa.

This hitherto widely accepted theory has been challenged of late. A study published in April and credited as the most comprehensive analysis to date of the bones of H floresiensis confidently reported that the tiny human also known as Flores Man, because his remains were discovered on the Indonesian island of Flores in 2003 was not descended from H erectus but most likely from another ancestor in Africa.

That study, led by Debbie Argue of the Australian National University (ANU), used 133 data points ranging across the skull, jaws, teeth, arms, legs and shoulders of the H. floresiensis fossil to conclude that many features were more primitive than H. erectus, and that therefore the hobbits were most likely a sister species of Homo habilis, one of the earliest known species of human found in Africa 1.75 million years ago. It was possible, Argues team said, that H. floresiensis evolved in Africa and migrated, or that a common ancestor moved from Africa then evolved into H. floresiensis.

Now Jos Alexandre Felizola Diniz-Filho of the Federal University of Gois, Brazil, and Pasquale Raia of University of Naples Federico II have revisited the controversy through their application of quantitative evolutionary genetics modelling, using simulations to evaluate the possible trajectories of body dwarfing between H. erectus (with an estimated body size value of 50 kg) and H. floresiensis (with a body size value of 27 kg).

The pair state their results, published in the journal Proceedings of the Royal Society B, do not say any final word on the matter, but their analysis does consistently support a relatively large-bodied hominid as the ancestor to H. floresiensis.

If H. floresiensis originated from an early small-bodied Homo such as such as H. habilis, they note, its small body and brain would just reflect deeper ancestry followed by little evolutionary change. However, that still leaves deep implications for the so-called Out of Africa I hypothesis, which portrays H. erectus or related forms as the first hominin to leave Africa.

On the other hand, the theory that H. floresiensis evolved from H. erectus also required understanding how Flores Man, given the small size not just of its body but also its brain, could be the evolutionary result of insular dwarfism due to the island rule, where the limited environment and resources of islands see smaller mainland animals become larger, while larger animals become smaller.

The pair report that the hobbits small body and brain size are perfectly consistent with dwarfing driven by strong directional selection under the island rule. Our results also show that the exceedingly small cranial volume of H. floresiensis might have required additional and independent selective forces acting on brain size alone, reinforcing the role of energetic constraints underlying the island rule.

Thus their findings also support previous conclusions that H. floresiensis may be most likely derived from an early Indonesian H. erectus, which is coherent with currently accepted biogeographical scenario for Homo expansion out of Africa.

The rest is here:
Genetic modelling adds a new twist to hobbit ancestry question - Cosmos

When it comes to attraction, the allure can begin even before she sets eyes on you. There seems to be something about the way youher dinnersmells from afar that makes you a desired target. While you are chatting with friends or overseeing the barbecue, that mosquito will go on the hunt and make you her next blood meal. But what makes you so attractive to tiny ankle biters?

This month a group of British researchers is launching a new investigation into the role of human genetics in this process. They are planning to collect smelly socks from 200 sets of identical and nonidentical twins, place the footwear in a wind tunnel with the bugs and see what happens next. The owners of the socks, the scientists hope, may naturally produce attractive or repellant chemicals that could become the basis for future mosquito control efforts. The researchers expect that studying the popularity of the garments the skeeters hone in onand analyzing both the odor compounds in them and the genetics of their ownerscould help.The study, which will include 100 twins each from the U.K. and from the Gambia, will start recruiting volunteers in the coming weeks.

We know very little about the genetics of what makes us attractive to mosquitoes, says James Logan, a medical entomologist at the London School of Hygiene and Tropical Medicine who is leading the work. Earlier studies suggest visual, olfactory and thermal (body heat) cues all help drive mosquito attraction. We hope this study will give us more insights into the mechanisms that help change our body odors to make us more or less attractive to mosquitos, he says. If we can identify important genes, perhaps we could develop a pill or medication that would allow the body to produce natural repellents to keep mosquitoes away. The findings, he adds, could also help epidemiologists improve their models for how vulnerable certain populations may be to disease-carrying mosquitoes.

Already scientists know there are differences among us that contribute to why some of us get bitten more. Those of us who exhale more carbon dioxide seem to be a natural beacon for mosquitoes, in particular. Researchers have also found a correlation with body size, with taller or larger people tending to attract more bitesperhaps because of their carbon dioxide output or body surface area. There is also some evidence women who are pregnant or at certain phases of the menstrual cycle are more attractive to mosquitoes. Other work has found that people infected with malaria are more attractive to malaria-carrying mosquitoes during their transmissible stage of infection.

But what of our individual genetics? Two years ago Logans team published a small study looking at 18 sets of identical twins and 19 sets of nonidentical twins and their attractiveness to mosquitoes. They found that identical twins were more similar in their desirability to the blood-sucking insects than the nonidentical twins. Because earlier work had found that identical twins smell more alike than nonidentical twins, the British researchers surmised genes may play a role in this mosquito attractiveness.

This new study aims to nail down some more concrete conclusions with its larger sample size and add another population into the mix. (Most research in this area has focused on European Caucasians whereas this study will also include twins from the Gambia). There are other differences that set this apart from their earlier work, too: The 2015 study had tested attractiveness among Aedes mosquitoesthose that carry dengue and Zikawhereas this study will test attractiveness among Anopheles mosquitoes, a species that can transmit malaria. The team suspects the different species will be attracted to the same volatile compounds in human odor but wants to explore this further.

This is novel work and its a good step. It will tell us if there are genetic differences or not but it wont be a complete answer about mosquito attraction because other factors like diet, wind, time of day and mosquito species can all influence that, says Zainulabeuddin Syed, a professor of biological sciences at the University of Notre Dame who studies the smell-influenced behavior and movement of insects and is not involved in the Logan project. Syeds work has found that people of various ethnic groups all seem to produce four major volatile compounds (although at varying levels) and there are some early hints that one compound in particular, called nonanal, may be particularly attractive, at least among certain species of mosquitoes.

Exactly what genes contribute to producing compounds that could possibly interest mosquitoes remains a vast unknown. Scientists that study human odors and genetics have previously suggested scent cues associated with genetics are likely controlled via the major histocompatibility complex (MHC) genes. Those genes appear to play a role in odor production and also in mammals mating choicesbecause humans and mice alike appear to prefer mates that smell less similar to themselves, which scientists have theorized may be a natural control against inbreeding. As a result, Logans team may target those odor-linked genes, but he says they are looking at all the options. In the next couple of years, he says, they hope to have some early answers. For now, and likely for many years to come, we can only slather on some bug repellant and hope for the best.

Here is the original post:
Are You a Magnet for Mosquitoes? - Scientific American - Scientific American

The WNT1 ligand has previously been identified in bone disease, but its role in bone homeostasis, its cellular source and targets in bone have only just recently been identified.The research, led by Dr. Brendan Lee at Baylor College of Medicine, appears in the Journal of Clinical Investigation.

To determine the bone-specific function of WNT1, the mutation that has been associated with recessive forms of Osteogenesis Imperfecta (OI) and other forms of early-onset osteoporosis, Lee, chair of the Department of Molecular and Human Genetics at Baylor, generated mouse models to study the consequences of both the loss and gain of WNT1 function in a specialized bone cell called the osteocyte.

This research builds on previous work that identified WNT1s role in coordination and its known effect on brain development. Now, we understand how this molecule works in bone, and this paper tells us that WNT1 is produced by osteocytes to control the activity of the bone-forming cell, the osteoblast, said Lee, also the Robert and Janice McNair Endowed Chair and professor of molecular and human genetics at Baylor.

The role of osteocytes, blasts and clasts

The over- or underexpression of WNT1 is controlled by osteocytes, or bone embedded cells. The osteocytes produce WNT1 to signal to bone-forming cells called osteoblasts that reside on the surface of bone via a biochemical pathway called mTORC1. When WNT1 is overexpressed by the osteocyte, bone formation is stimulated due to an increase in osteoblast numbers and collagen production following the activation of the mTORC1 pathway in these cells.

Osteocytes are embedded in the bone, with osteoblasts and osteoclasts sitting on the surface adding or removing bone, respectively, explained Lee. It turns out, osteocytes are actually the master controllers of this balance of bone formation and resorption in part by acting as either a receiver or sender of WNT signals.

We knew previously from others work that osteocytes could inhibit bone formation by producing the protein sclerostin, which represses osteoblast function. This research brings the cycle of information full circle by showing that while sclerostin turns the osteoblasts off, WNT1 from osteocytes turns them on, Lee said.

On the other hand, loss of WNT1 function resulted in low bone mass and spontaneous fracturing, similar to that seen in patients with OI. In this case, the osteocyte is not producing WNT1. However, osteocytes also can receive WNT signals themselves, leading them to control the activity of bone-removing cells, the osteoclasts.

Therapeutic impact

Primary therapies traditionally used to treat OI have shown limited efficacy in combating WNT1-related OI and osteoporosis. However, Lee and his research team identified anti-sclerostin antibody (Scl-Ab) treatment is effective in augmenting the action of other WNT ligands to improve bone mass and to significantly decrease the number of fractures in swaying mice, a model of WNT1 related OI and osteoporosis.

The results of this study, while conducted in mice, have important implications for the treatment of OI and osteoporosis in humans down the road, Lee said. By blocking sclerostin, the bone can be repaired effectively in diseases related to loss of WNT1 suggesting a personalized therapy. This is exciting especially as a promising anti-sclerostin drug is already in clinical development.

This work was supported by the Baylor College of Medicine Intellectual and Developmental Disabilities Research Center from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the Baylor College of Medicine Advance Cores with funding from the National Institutes of Health, the National Institute of Arthritis and Musculoskeletal and Skin Diseases, the Rolanette and Berdon Lawrence Bone Disease of Texas and the Center for Skeletal Medicine and Biology at Baylor College of Medicine.

Other contributors to this work include Kyu Sang Jeong, Yi-Chien Lee, Yuqing Chen, Ming-Ming Jiang and Elda Munivez, all of whom are with Baylor, and Catherine Ambrose with the University of Texas Health Science Center at Houston.

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Research shows bone-building protein can be used in therapy - Baylor College of Medicine News (press release)