Category Archives: Human Genetics

By Duke Medicine News and Communications

Thomas D. Petes, PhD, has been named the 2013 recipient of the Thomas Hunt Morgan Medal for lifetime achievement in the field of genetics from the Genetics Society of America. Petes, the Minnie Geller Professor of Molecular Genetics and Microbiology at Duke University School of Medicine, specializes in the study of yeast as a model for understanding genomic instability and chromosomal abnormalities commonly found in cancer cells. "Tom Petes research on cell division in yeast has direct relevance for human cells and the proteins involved in DNA repair, with important implications for understanding genetic defects that cause cancer," said Nancy Andrews, M.D., PhD., dean of the Duke University School of Medicine. "It is a powerful example of how the most fundamental, basic science research can have tremendous importance for understanding and treating human diseases. Petes and his colleagues have discovered striking similarities between yeast and human cells in the structure and function of proteins involved in DNA repair and in the protection of the tips of chromosomes. The similarities have yielded new insight into how normal cells become cancerous. For example, yeast cells lacking particular DNA mismatch repair enzymes exhibit genetic instabilities also found in human colorectal cancer cells, a finding that suggested the repair defects might play an important role in the disease process. Notably, Petes was among the first to apply these findings to hereditary non-polyposis colon cancer, an inherited syndrome in which 80 percent of patients develop intestinal tumors. Petes predicted that afflicted patients might similarly have mismatch repair mutations. The Petes lab also identified a gene in yeast required for maintenance of the tips of chromosomes that was closely related to a human gene mutated in patients with the cancer-prone disease ataxia telangiectasia. "Dr. Petes' rigorous work over the years in a model organism, in this case, yeast, is a wonderful example of how studies of model organisms can inform us about mechanisms of human disease, in this case, cancer, said Michael B. Kastan, M.D., PhD, executive director of the Duke Cancer Institute and the William W. Shingleton Professor of Pharmacology and Cancer Biology. He is richly deserving of this award for a superior body of work." Petes received his PhD in genetics at the University of Washington in Seattle. He then went on to postdoctoral fellowships at the National Institute for Medical Research in London and the Massachusetts Institute of Technology in Cambridge. In 2002, Petes served as president of the Genetics Society of America, and was the chair of the Department of Molecular Genetics and Microbiology at Duke from 2004-2009. He has been a member of the National Academy of Sciences since 1999; was named to the American Academy of Arts & Sciences in 2005; and became a fellow in the American Academy of Microbiology in 2009. The Thomas Hunt Morgan Medal is awarded for lifetime contributions to the science of genetics. It recognizes the full body of work of an exceptional geneticist, and recipients have made substantial contributions throughout their careers. The Medal was established by the Genetics Society of America in 1981 and named in honor of Thomas Hunt Morgan, who received a 1933 Nobel Prize for his findings, which provided the first experimental evidence that chromosomes are the carriers of genetic information.

Continued here:
Petes Wins Lifetime Achievement Award in Genetics

SALT LAKE CITY, Oct. 15, 2012 (GLOBE NEWSWIRE) -- Myriad Genetics, Inc. (MYGN) today announced that it will issue financial results for the first fiscal quarter 2013 following the close of market on Monday, November 5, 2012.

The Company will also host a conference call on Monday, November 5, 2012 at 4:30 P.M. Eastern to review the financial results. Participating on the call will be: Peter Meldrum, President and Chief Executive Officer, Mark Capone, President of Myriad Genetic Laboratories, Inc. and Jim Evans, Chief Financial Officer.

To listen to the call, interested parties may dial 800-354-6885 or 303-223-2680. All callers will be asked to reference reservation number 21607424.

The conference call will also be available through a live webcast at http://www.myriad.com.

A replay of the call will be available two hours after the end of the call for seven days and may be accessed by dialing 800-633-8284 or 402-977-9140 and entering reservation number 21607424.

About Myriad Genetics

Myriad Genetics is a leading molecular diagnostic company dedicated to making a difference in patient's lives through the discovery and commercialization of transformative tests to assess a person's risk of developing disease, guide treatment decisions and assess risk of disease progression and recurrence. Myriad's portfolio of molecular diagnostic tests are based on an understanding of the role genes play in human disease and were developed with a commitment to improving an individual's decision making process for monitoring and treating disease. Myriad is focused on strategic directives to introduce new products, including companion diagnostics, as well as expanding internationally. For more information on how Myriad is making a difference, please visit the Company's website: http://www.myriad.com

Myriad, the Myriad logo, BRACAnalysis, Colaris, Colaris AP, Melaris, TheraGuide, Prezeon, OnDose, Panexia and Prolaris are trademarks or registered trademarks of Myriad Genetics, Inc. in the United States and foreign countries. MYGN-F, MYGN-G

Continue reading here:
Myriad Genetics to Announce First Fiscal Quarter 2013 Results on Monday, November 5, 2012

Public release date: 15-Oct-2012 [ | E-mail | Share ]

Contact: Phyllis Edelman pedelman@genetics-gsa.org 301-634-7302 Genetics Society of America

BETHESDA, MD -- October 15, 2012 -- The Genetics Society of America (GSA) is pleased to announce its 2013 award recipients. The five individuals honored are recognized by their peers for their outstanding achievements and contributions to the community of geneticists. They will receive their awards at GSA conferences during 2013.

"This year's award winners are an outstanding group of individuals who have all contributed in such powerful ways to the field of genetics in research, in education, and in fostering the genetics community. The GSA awards provide an opportunity for the genetics community as a whole to say a heartfelt thank you and to recognize those whose impressive achievements have advanced the science of genetics," said Phil Heiter, PhD, President of GSA.

The recipients of the 2013 GSA Awards are as follows:

Additional information about each of the awards and the recipients' achievement is listed below.

Recipient: Thomas D. Petes, PhD, Duke University Award: The Thomas Hunt Morgan Medal

Dr. Petes is the Minnie Geller Professor in Genetics in the Department of Molecular Genetics and Microbiology at Duke University Medical Center in Durham, NC. He has made seminal research contributions that have furthered the understanding of the mechanisms of DNA damage and repair using the yeast Saccharomyces cerevisiae as a model system. His insights into comprehending genome stability and instability extend far beyond this model system, laying the foundation for much of our knowledge about how human cells replicate, protect, repair and combine their chromosomes. This has provided crucial understanding in identifying the gene defects of the most common form of hereditary colon cancer and in other human diseases.

In addition to his scientific achievements, Dr. Petes has mentored numerous outstanding scientists and has been an active member of GSA, having served as both secretary (1995) and president (2002) of the Society. He has been honored by election to the National Academy of Sciences (1999) and as a fellow of the American Academy of Arts and Sciences (2005), the American Association for the Advancement of Science (2005), and the American Academy of Microbiology (2009).

The Thomas Hunt Morgan Medal is named in honor of Thomas Hunt Morgan (1866), the classical geneticist who was a founder of modern genetics and the 1933 Nobel Prize in Physiology or Medicine recipient for his studies of Drosophila and "the role played by the chromosome in heredity." The Morgan Medal recognizes genetics researchers whose body of work over their lifetime has substantively added to knowledge in the field and consequently has had great impact on its direction.

View post:
Genetics Society of America announces 2013 award recipients

Walking up the stairs of the Faculty of Medicine, which reminded me of a colonial English Mansion with an imposing regal atmosphere, I finally found the Office of the Dean.

In his spacious office sat Professor Rohan W. Jayasekara, Dean of the Faculty of Medicine who is a pioneer in the field of Medical Genetics in Sri Lanka. He is the person who established the first Human Genetics Unit in the country in 1983. Professor Jayasekara appeared to be extremely affable with a most friendly disposition and he immediately put one at ease. This is his interview with Reminiscences of Gold.

Professor Rohan Jayasekara

I was born in Colombo and had my upbringing in Mount Lavinia. I was the only child in the family. The childhood I spent in the early 50s was a laid back setup where things moved at a leisurely pace. Children got their education but at the same time they enjoyed their childhood. School began at 8.45 am and finished at 3.15 in the afternoon. So after a good breakfast, we went to school with a lunch break of one hour from 12.15pm - 1.15pm. We could even play a cricket match continuing the next day. Classes finished at 3.15 pm and those who wanted to play sports could stay on in the college.

Others came home and played the usual cricket, rugby and football in our garden. All the neighbours were one family. My father was an old Peterite so he sent me to St. Peters. There was strict discipline at St. Peters but at the same time there was a lot of freedom and we had a proper moulding. I owe so much to my old school. The important thing during that era was that we didnt have television. I remember coming to the British Council very regularly because I used to finish two books every week. We developed our reading habits which helped improve our command of the language, explained Jayasekara.

He joined the Faculty of Medicine at the Peradeniya University in 1967 where he spent five years. Those were the best years of my life and it was one of the most beautiful universities in the world. We had a balanced life. We thoroughly enjoyed seeing plays in the Open Arts Theatre. There were very dedicated teachers and there were the likes of Professor Bibile who had musical evenings in their homes. It was an enriching experience. I always felt that the graduates of Peradeniya had a kindred spirit. Maybe because we lived together, ate and drank together, enjoyed, celebrated and cried together. The 1971 JVP insurrection was the only tragic experience we had. Some lost their lives.

Jayasekera joined the Faculty of Medicine as a lecturer in 1974. He left the island in 1977 for his postgraduate studies at the Department of Human Genetics, University of Newcastle upon Tyne. Its a beautiful university town with friendly people. We learnt not only the subject matter but also other character moulding traits: how to communicate with people, how to be polite and how to disagree with people and how to control oneself. I have never seen any British professional throwing tantrums. Not even under the harshest of provocations. I have never seen my boss losing his temper. They had a way about them.

I had a very interesting experience during my stay in England. Besides my Ph.D. certificate, I also have a certificate from the Chief Constable of Northern England, the equivalent of our IGP there because I helped them arrest red handed a gang of car thieves. I used to work on the fourth floor of the Human Genetics Unit from where I could see the car park. One day I looked down at the car park and saw my car there. Fifteen minutes later I noticed that my red car was missing. So I phoned the Police. A week later they came home and knocked on the door and the people in my flat thought that I had committed a crime. My car had been found in Glasgow because some football hooligans had taken it there. It had been full of empty bottles of beer. A few months later, when I was looking down at the car park, I saw some guys trying to open some cars in the car park. I quickly rang the cops, and in five minutes, four panda cars rushed in and they caught the thieves red handed. Then they came up to the fourth floor looking for Dr. J and I identified myself. Three weeks later I got a letter from the Chief of Police saying : we greatly appreciate your action which helped us in arresting the car thieves and breaking a ring of crime that has been going on there. My boss Professor Roberts said: Chum, this is more valuable than your Ph.D. certificate. I felt happy because I did something good for the community.

Jayasekara returned to the island in 1980 having obtained a Ph.D. in Cytogenetics, which was a pioneering field at the time. The study of Human Genetics has far-reaching consequences for the health of any nation. Jayasekara established the first Human Genetics Unit in the country in 1983. When I came back from England, I was determined not to waste my knowledge and skills so I decided to start the unit. With the initial assistance of the WHO, I managed to build it up. Now we have collaborations and link programmes with several institutes abroad. We conduct teaching programmes for other faculties, institutes and colleges.

We have trained five doctors as clinical geneticists. Now it can run on its own and it is quite independent. I dont even have to sight the place because it is running really well. Im blessed with good people. Now there are 30 people in the unit. Our biggest problem is the lack of space and that is the only constraint. We have an abundance of talent. People are enthusiastic and they need to be encouraged and nurtured. Our talent is unmatched anywhere in the world. So my ambition is to see that every main town has a Human Genetics Unit.

Read the original post:
Master-builder of the Human Genetics Unit

Genoeconomists' use of population-genetic data to predict economic success is sparking a war of words, including charges of racism

By Ewen Callaway and Nature magazine

The United States has the right amount of genetic diversity to buoy its economy, claim economists. Image: D. ACKER/BLOOMBERG VIA GETTY

Showcasing more than fifty of the most provocative, original, and significant online essays from 2011, The Best Science Writing Online 2012 will change the way...

Read More

From Nature magazine

The invalid assumption that correlation implies cause is probably among the two or three most serious and common errors of human reasoning. Evolutionary biologist Stephen Jay Gould was referring to purported links between genetics and an individuals intelligence when he made this familiar complaint in his 1981 book The Mismeasure of Man.

Fast-forward three decades, and leading geneticists and anthropologists are levelling a similar charge at economics researchers who claim that a countrys genetic diversity can predict the success of its economy. To critics, the economists paper seems to suggest that a countrys poverty could be the result of its citizens genetic make-up, and the paper is attracting charges of genetic determinism, and even racism. But the economists say that they have been misunderstood, and are merely using genetics as a proxy for other factors that can drive an economy, such as history and culture. The debate holds cautionary lessons for a nascent field that blends genetics with economics, sometimes called genoeconomics. The work could have real-world pay-offs, such as helping policy-makers to set the right level of immigration to boost the economy, says Enrico Spolaore, an economist at Tufts University near Boston, Massachusetts, who has also used global genetic-diversity data in his research.

But the economists at the forefront of this field clearly need to be prepared for harsh scrutiny of their techniques and conclusions. At the centre of the storm is a 107-page paper by Oded Galor of Brown University in Providence, Rhode Island, and Quamrul Ashraf of Williams College in Williamstown, Massachusetts. It has been peer-reviewed by economists and biologists, and will soon appear in American Economic Review, one of the most prestigious economics journals.

The paper argues that there are strong links between estimates of genetic diversity for 145 countries and per-capita incomes, even after accounting for myriad factors such as economic-based migration. High genetic diversity in a countrys population is linked with greater innovation, the paper says, because diverse populations have a greater range of cognitive abilities and styles. By contrast, low genetic diversity tends to produce societies with greater interpersonal trust, because there are fewer differences between populations. Countries with intermediate levels of diversity, such as the United States, balance these factors and have the most productive economies as a result, the economists conclude.

More here:
Claim That Links Economic Success and Genetic Diversity Draws Criticism

Public release date: 11-Oct-2012 [ | E-mail | Share ]

Contact: Kenneth Krauter krauter@colorado.edu 303-492-6693 University of Colorado at Boulder

A new long-term study of human twins by University of Colorado Boulder researchers indicates the makeup of the population of bacteria bathing in their saliva is driven more by environmental factors than heritability.

The study compares saliva samples from identical and fraternal twins to see how much "bacterial communities" in saliva vary from mouth to mouth at different points in time, said study leader and CU-Boulder Professor Kenneth Krauter. The twin studies show that the environment, rather than a person's genetic background, is more important in determining the types of microbes that live in the mouth.

For the new study, doctoral student Simone Stahringer sequenced the microbial DNA present in the saliva samples of twins. She and the research team then determined the microbes' identities through comparison with a microbe sequence database. Saliva samples were gathered from twins over the course of a decade beginning in adolescence to see how salivary microbes change with time.

After determining the oral "microbiomes" of identical twins, who share the same environment and genes, and the microbiomes of fraternal twins who share only half their genes, the researchers found the salivary microbes of the identical twins were not significantly more similar to each other than to those of fraternal twins. "We concluded the human genome does not significantly affect which bacteria are living in a person's mouth," said Krauter of CU-Boulder's molecular, cellular and developmental biology department. "It appears to be more of an environmental effect."

Krauter said while the twin data from the oral microbiome study indicates that genetics plays a more minor role, it's possible the genes still affect the oral microbiome in more subtle ways -- an effect he plans to further explore.

A paper on the subject was published online Oct. 12 in the journal Genome Research. Other co-authors included doctoral student William Walters of MCD Biology, Jose Clemente and Rob Knight of the chemistry and biochemistry department, Robin Corley and John Hewitt of the Institute for Behavioral Genetics and Dan Knights, a former doctoral student in the computer science department.

The researchers also found that the salivary microbiome changed the most during early adolescence, between the ages of 12 and 17. This discovery suggests that hormones or lifestyle changes at this age might be important, according to the team.

Stahringer said that when several pairs of identical twins moved out of their homes and, for example, went off to college, the oral microbes they carried changed, which is consistent with the idea that the environment contributes to the types of microbes in the saliva. "We were intrigued to see that the microbiota of twin pairs became less similar once they moved apart from each other," Stahringer said.

Continued here:
Nurture trumps nature in study of oral bacteria in human twins, says CU study

ScienceDaily (Oct. 11, 2012) A new long-term study of human twins by University of Colorado Boulder researchers indicates the makeup of the population of bacteria bathing in their saliva is driven more by environmental factors than heritability.

The study compares saliva samples from identical and fraternal twins to see how much "bacterial communities" in saliva vary from mouth to mouth at different points in time, said study leader and CU-Boulder Professor Kenneth Krauter. The twin studies show that the environment, rather than a person's genetic background, is more important in determining the types of microbes that live in the mouth.

For the new study, doctoral student Simone Stahringer sequenced the microbial DNA present in the saliva samples of twins. She and the research team then determined the microbes' identities through comparison with a microbe sequence database. Saliva samples were gathered from twins over the course of a decade beginning in adolescence to see how salivary microbes change with time.

After determining the oral "microbiomes" of identical twins, who share the same environment and genes, and the microbiomes of fraternal twins who share only half their genes, the researchers found the salivary microbes of the identical twins were not significantly more similar to each other than to those of fraternal twins. "We concluded the human genome does not significantly affect which bacteria are living in a person's mouth," said Krauter of CU-Boulder's molecular, cellular and developmental biology department. "It appears to be more of an environmental effect."

Krauter said while the twin data from the oral microbiome study indicates that genetics plays a more minor role, it's possible the genes still affect the oral microbiome in more subtle ways -- an effect he plans to further explore.

A paper on the subject was published online Oct. 12 in the journal Genome Research. Other co-authors included doctoral student William Walters of MCD Biology, Jose Clemente and Rob Knight of the chemistry and biochemistry department, Robin Corley and John Hewitt of the Institute for Behavioral Genetics and Dan Knights, a former doctoral student in the computer science department.

The researchers also found that the salivary microbiome changed the most during early adolescence, between the ages of 12 and 17. This discovery suggests that hormones or lifestyle changes at this age might be important, according to the team.

Stahringer said that when several pairs of identical twins moved out of their homes and, for example, went off to college, the oral microbes they carried changed, which is consistent with the idea that the environment contributes to the types of microbes in the saliva. "We were intrigued to see that the microbiota of twin pairs became less similar once they moved apart from each other," Stahringer said.

Krauter said there appears to be a core community of oral bacteria that is present in nearly all humans studied. "Though there are definitely differences among different people, there is a relatively high degree of sharing similar microbial species in all human mouths," he said.

The authors say the new study has established a framework for future studies of the factors that influence oral microbial communities. "With broad knowledge of the organisms we expect to find in mouths, we can now better understand how oral hygiene and environmental exposure to substances like alcohol, methamphetamines and even foods we eat affect the balance of microbes," said Krauter.

The rest is here:
Nurture trumps nature in study of oral bacteria in human twins, study finds

The United States has the right amount of genetic diversity to buoy its economy, claim economists.

D. ACKER/BLOOMBERG VIA GETTY

The invalid assumption that correlation implies cause is probably among the two or three most serious and common errors of human reasoning. Evolutionary biologist Stephen Jay Gould was referring to purported links between genetics and an individuals intelligence when he made this familiar complaint in his 1981 book The Mismeasure of Man.

Fast-forward three decades, and leading geneticists and anthropologists are levelling a similar charge at economics researchers who claim that a countrys genetic diversity can predict the success of its economy. To critics, the economists paperseems to suggest that a countrys poverty could be the result of its citizens genetic make-up, and the paper is attracting charges of genetic determinism, and even racism. But the economists say that they have been misunderstood, and are merely using genetics as a proxy for other factors that can drive an economy, such as history and culture. The debate holds cautionary lessons for a nascent field that blends genetics with economics, sometimes called genoeconomics. The work could have real-world pay-offs, such as helping policy-makers to set the right level of immigration to boost the economy, says Enrico Spolaore, an economist at Tufts University near Boston, Massachusetts, who has also used global genetic-diversity data in his research.

But the economists at the forefront of this field clearly need to be prepared for harsh scrutiny of their techniques and conclusions. At the centre of the storm is a 107-page paper by Oded Galor of Brown University in Providence, Rhode Island, and Quamrul Ashraf of Williams College in Williamstown, Massachusetts1. It has been peer-reviewed by economists and biologists, and will soon appear in American Economic Review, one of the most prestigious economics journals.

The paper argues that there are strong links between estimates of genetic diversity for 145countries and per-capita incomes, even after accounting for myriad factors such as economic-based migration. High genetic diversity in a countrys population is linked with greater innovation, the paper says, because diverse populations have a greater range of cognitive abilities and styles. By contrast, low genetic diversity tends to produce societies with greater interpersonal trust, because there are fewer differences between populations. Countries with intermediate levels of diversity, such as the United States, balance these factors and have the most productive economies as a result, the economists conclude.

The manuscript had been circulating on the Internet for more than two years, garnering little attention outside economics until last month, when Science published a summary of the paper in its section on new research in other journals. This sparked a sharp response from a long list of prominent scientists, including geneticist David Reich of Harvard Medical School in Boston, Massachusetts, and Harvard University palaeoanthropologist Daniel Lieberman in Cambridge.

In an open letter, the group said that it is worried about the political implications of the economists work: the suggestion that an ideal level of genetic variation could foster economic growth and could even be engineered has the potential to be misused with frightening consequences to justify indefensible practices such as ethnic cleansing or genocide, it said.

Our study is not about a nature or nurture debate.

The critics add that the economists made blunders such as treating the genetic diversity of different countries as independent data, when they are intrinsically linked by human migration and shared history. Its a misuse of data, says Reich, which undermines the papers main conclusions. The populations of East Asian countries share a common genetic history, and cultural practicesbut the former is not necessarily responsible for the latter. Such haphazard methods and erroneous assumptions of statistical independence could equally find a genetic cause for the use of chopsticks, the critics wrote.

Continued here:
Economics and genetics meet in uneasy union

In a groundbreaking study hailed as a roadmap for new targeted treatments, Professor Charles Perou and his colleagues collected DNA and tumor samples from 825 breast cancer patients for the first comprehensive look at the underlying genetics behind the deadly disease.

The researchers conducted an exhaustive examination of all 20,000 or so genes in the human body for each sample. They were looking for patterns of genetic mutations that promote the tumors and can potentially be counteracted with new or even existing drugs.

Its a mountain of data, but Perou never forgets those samples came from real human beings grappling with a terrifying diagnosis.

Its what drives him.

Dozens of those women will likely die of the disease. Some surely already have in just the few years since the samples were collected.

I think about that all the time. Personally, its a huge motivation for me. These studies are dealing with real human beings and every death is a tragedy, said Perou, a professor of genetics at the University of North Carolina and the lead author on the study which was published in the journal Nature and is part of a large federal project, the Cancer Genome Atlas, looking at genetic mutations associated with various types of cancer.

Perou said the term genetics can be confusing. Whats at issue is not the so-called breast cancer genes, by which a person inherits a susceptibility to breast cancer. About 10 percent of women with breast cancer fall into that category.

We are talking about the other 90 percent of women who are presumably born with no particular tendency to develop the disease. For those women, one in eight will develop breast cancer and seven in eight will not.

In all those cases, there are genetic mutations that cause the disease, Perou said.

The genome study does not address the vital but murky question of what causes those mutations.

Read the original:
Outsmarting breast cancer

An international team led by investigators at the French National Institute for Agricultural Research, the US Department of Energy's Joint Genome Institute, and the Wellcome Trust Centre for Human Genetics presents results from a genome sequencing study of the button mushroom, Agaricus bisporus, in the early, online issue of the Proceedings of the National Academy of Sciences. The team generated draft genome sequences for two A. bisporus representatives a cultivated European strain from the A. bisporus variety bisporus and a California strain from the burnetti variety that makes it home in the leaf litter around woody plants. By folding in transcriptome data for different mushroom developmental stages and for mushrooms grown on different substrates, the group uncovered clues about the fungal adaptations that the mushroom uses for growth in humic acid-rich environments, including genes coding for enzymes involved in the decomposition of leaves and other plant materials.

Adult stress levels and socio-economic status during childhood appear to influence some DNA methylation differences that exist between individuals within a community, according to a study by researchers at the University of British Columbia, Simon Fraser University, and Stanford University. The researchers performed array-based DNA methylation profiling on peripheral mononuclear white blood cells from 92 individuals between the ages of 24 and 45 from a community in and around Vancouver, Canada. When they looked at how methylation patterns at the promoters of nearly 14,500 human genes corresponded to individuals' gene expression profiles, blood composition, early-life socio-economic status and so on, the researchers found several factors that seemed to coincide with inter-individual methylation differences. These included the proportion of different white blood cell types present in the individuals' sample, their stress hormone output sex, age, and ethnicity as well as experiences such as childhood poverty and stress during adulthood. Even so, the DNA methylation differences detected often did not coincide with gene expression shifts at nearby genes, the researchers reported, "suggesting a more complex relationship than anticipated."

Another PNAS study looks at the bacterioplankton communities present in ocean samples collected in the Antarctic and the Arctic. By sequencing the V6 region of the 16S ribosomal RNA gene, Desert Research Institute investigators Alison Murray and colleagues from several centers around the world catalogued the bacteria found in surface or deep water bacterioplankton communities in the Southern and Arctic Oceans. The researchers then looked at how deep-water and shallow-water communities in the 20 Southern Ocean samples and the 24 Arctic Ocean samples tested compared with one another and with four-dozen samples collected at lower latitude ocean sites. "Our results suggest differences in environmental conditions at the poles and different selection mechanisms controlling surface and deep ocean community structure and diversity," the study's authors say. "Surface bacterioplankton may be subjected to more short-term variable conditions, whereas deep communities appear to be structured by longer water-mass residence times and connectivity through ocean circulation."

Read the rest here:
This Week in PNAS