(Press-News.org) Researchers from Osaka University and the National Institute for Basic Biology, Japan, have found a highly significant connection between the molecular mechanisms underlying genetic and environmental sex determination. The scientists report in the open-access journal PLoS Genetics the identification of a gene responsible for the production of males during environmental sex determination in the crustacean Daphnia.
Ways in which an individual organism's sex is determined are diverse among animal lineages and can be broadly divided into two major categories: genetic and environmental. In genetic sex determination (GSD), sex-specific differentiation results from intrinsic genetic differences between males and females, whereas environmental sex determination (ESD) relies upon environmental signals to induce male or female sex determination. In contrast to GSD models, the genetics of ESD organisms are poorly understood.
The researchers cloned Doublesex (Dsx) genes from Daphnia magna, a freshwater brachiopod crustacean that clones itself to produce males in response to certain environmental cues. The Dsx genes play an important role in controlling sexual differences in organisms using GSD such as nematodes, insects, and vertebrates. Knocking out one particular Dsx gene, DapmaDsx1, in male embryos resulted in the production of female traits including ovarian maturation, whereas ectopic expression of DapmaDsx1 in female embryos resulted in the development of male-like phenotypes.
The researchers infer that there is an ancient, previously unidentified link between genetic and environmental sex determination. This study was confined only to the role of Dsx in ESD, so it would be highly desirable to establish the link between the environmental signal and Dsx expression. However, this work lends support to the "Doublesex hypothesis" of sex determination, in which many different sorts of upstream regulatory pathways could converge on Dsx-family genes, which would serve as the basis of sexual differentiation mechanisms across the animal kingdom.
INFORMATION:
FINANCIAL DISCLOSURE: This study was partly supported through grants from Grants-in-Aid from Ministry of Education, Culture, Sport, Science, and Technology (to HW), grants from Ministry of the Environment of Japan, and a grant of Long-Range Research Initiative (LRI) by Japan Chemical Industry Association (JCIA) (to TI). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
COMPETING INTERESTS: The authors have declared that no competing interests exist.
CITATION: Kato Y, Kobayashi K, Watanabe H, Iguchi T (2011) Environmental Sex Determination in the Branchiopod Crustacean Daphnia magna: Deep Conservation
of a Doublesex Gene in the Sex-Determining Pathway. PLoS Genet 7(3): e1001345. doi:10.1371/journal.pgen.1001345
PLEASE ADD THIS LINK TO THE FREELY AVAILABLE ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (the link will go live when the embargo ends): http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1001345
CONTACT: Taisen Iguchi
taiseni@hotmail.co.jp
Disclaimer
This press release refers to an upcoming article in PLoS Genetics. The release is provided by journal staff, or by the article authors and/or their institutions. Any opinions expressed in this release or article are the personal views of the journal staff and/or article contributors, and do not necessarily represent the views or policies of PLoS. PLoS expressly disclaims any and all warranties and liability in connection with the information found in the releases and articles and your use of such information.
About PLoS Genetics
PLoS Genetics (http://www.plosgenetics.org) reflects the full breadth and interdisciplinary nature of genetics and genomics research by publishing outstanding original contributions in all areas of biology. All works published in PLoS Genetics are open access. Everything is immediately and freely available online throughout the world subject only to the condition that the original authorship and source are properly attributed. Copyright is retained by the authors. The Public Library of Science uses the Creative Commons Attribution License.
About the Public Library of Science
The Public Library of Science (PLoS) is a non-profit organization of scientists and physicians committed to making the world's scientific and medical literature a freely available public resource. For more information, visit http://www.plos.org.
END
Weight gain in adults coincided with increased consumption of added sugars, in a study reported today at the American Heart Association's Nutrition, Physical Activity and Metabolism/Cardiovascular Disease Epidemiology and Prevention 2011 Scientific Sessions. Added sugars are sugars and syrups added to foods during processing, preparation, or at the table.
Researchers reviewed added sugars intake and patterns of body weight over 27 years using data collected in the Minnesota Heart Survey, a surveillance study of adults ages 25 to 74 living in the Minneapolis-St. Paul metropolitan ...
Contrary to intuition, people who suffer from the motor and vocal tics characteristic of Tourette syndrome actually perform behavioral tests of cognitive motor control more accurately and quickly than their typically developing peers do. According to evidence reported online on March 24 in Current Biology, a Cell Press publication, that enhanced control arises from structural and functional changes in the brain that likely come about from the need to constantly suppress tics.
"The motor outputs of children with Tourette syndrome are under greater cognitive control," ...
Researchers in Texas have discovered thousands of human artifacts in a layer of earth that lies directly beneath an assemblage of Clovis relics, expanding evidence that other cultures preceded the Clovis culture in North America. This pre-Clovis toolkit appears to be between 13,200 and 15,500 years old and it includes biface and blade technology that may have later been adapted—and improved upon—by the Clovis culture.
The Clovis people, whose tools were known for their distinctive "fluted" points, were once thought to be the original settlers of North America about 13,000 ...
Most regular online slots players have their good nights when they get lucky and have a fun winning streak. But, to win $10,000 or more on every game you try is every online casino player's dream. This dream came true at JackpotCapital.com last week when one lucky player tried six online slot machines during a two-day period and walked away with a total of $139,957.77 in winnings.
"I had played Aladdin's Wishes before. In fact, I had a bit of luck on it last time I played so I started there. I couldn't believe it when I won $29,305!" said the winner from the undisclosed ...
Researchers excavating a creek bed in central Texas have found evidence suggesting humans settled in North America some two thousand years earlier than previously estimated.
The findings are reported in the March 25 issue of Science.
Earth scientists at the University of Illinois at Chicago determined the age using an optical dating technique. They linked sediment and mineral samples to human artifacts and tools found in a single stratigraphic layer located below younger, previously dated Paleo-Indian Clovis-culture artifacts.
Texas A&M University anthropologist Michael ...
PHILADELPHIA - Researchers at the University of Pennsylvania's Abramson Cancer Center have discovered a novel way of treating pancreatic cancer by activating the immune system to destroy the cancer's scaffolding. The strategy was tested in a small cohort of patients with advanced pancreatic cancer, several of whose tumors shrank substantially. The team believes their findings – and the novel way in which they uncovered them -- could lead to quicker, less expensive cancer drug development.
The authors call the results, published in the March 25 issue of Science, a big ...
COLLEGE STATION, March 24, 2011— New discoveries at a Central Texas archaeological site by a Texas A&M University-led research team prove that people lived in the region far earlier – as much as 2,500 years earlier – than previously believed, rewriting what anthropologists know about when the first inhabitants arrived in North America. That pushes the arrival date back to about 15,500 years ago.
Michael Waters, director of Texas A&M's Center for the Study of First Americans, along with researchers from Baylor University, the University of Illinois-Chicago, the University ...
FitnessCouponClub.com has launched a service that helps to bring fitness professionals and companies together with fitness conscious consumers. By offering a group buying opportunity on the website, fitness companies can offer their services to fitness enthusiasts and fanatics who are looking for a deal on fitness classes, personal training and other fitness services or products. They even offer the opportunity to market worldwide if the service or product meets certain standards.
Following group buying trends, many companies have increased their clientele by offering ...
ANN ARBOR, Mich.---When local residents are allowed to make rules about managing nearby forests, the forests are more likely to provide greater economic benefits to households and contain more biodiversity, two University of Michigan researchers and a colleague conclude from an analysis of forest practices in tropical developing countries of East Africa and South Asia.
Lauren Persha and Arun Agrawal of the University of Michigan and Ashwini Chhatre of the University of Illinois used evidence from more than 80 forest sites in six tropical countries to test how local participation ...
Stroke patients who received electrical brain stimulation coupled with swallowing exercises showed greater improvement in swallowing ability than patients who did not receive this stimulation, according to a pilot study reported in Stroke: Journal of the American Heart Association.
Difficulty swallowing, known as dysphagia, is a common and serious stroke complication. It can lead to aspiration, when food or foreign matter accidentally enters the lungs causing pneumonia. Aspiration and aspiration pneumonia are common complications after stroke and can be deadly.
The ...
