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Archive - Oct 2015

October 7th

48-Million-Year-Old Fossil of Horse-Like Fetus Analyzed; Material Included Preserved Soft Tissue Like the Uteroplacenta and One Broad Uterine Ligament; May Be Earliest Fossil Record of Uterine System of Placental Mammal

Analysis of a 48-million-year-old fossil of a horse-like equoid fetus discovered, together with the fossil of its mother, in 2000 at the Messel pit near Frankfurt, Germany, is reported in a study published online on October 7, 2015 in the open-access journal PLOS ONE. The report was authored by Jens Lorenz Franzen, Ph.D., from Senckenberg Research Institute in Frankfurt, Germany, and also from the Naturhistorisches Museum in Basel, Switzerland, together with colleagues. The article is titled “Description of a Well Preserved Fetus of the European Eocene Equoid Eurohippus messelensis.” The authors of this study completed their investigation of the fetus from a 48-million-year-old horse-like equoid uncovered near Frankfurt, Germany, in 2000. They evaluated the bones and anatomy and used scanning electronic microscopy (SEM) and high-resolution micro-x-ray technologies to describe the ~12.5 cm fetus. The fetus appears to be well-preserved, with almost all bones present and connected, except for the skull, which appears to have been crushed. The well-preserved condition of the fossil allowed the researchers to reconstruct the original appearance and position of the fetus. They estimate that the mare may have died shortly before birth, but they don't believe the death was related to birth. The authors also found preserved soft tissue, like the uteroplacenta and one broad uterine ligament, which may represent the earliest fossil record of the uterine system of a placental mammal. Applying SEM, the authors discovered a bacterial lawn replacing the soft tissues, as is common with other specimens found in that area. The observable details correspond largely with living mares, which lead the authors to posit that the reproductive system was already highly developed during the Paleocene era, and possibly even earlier.

Fluid on Feet of Insects May Enhance Ability to Quickly Release the Foot, Rather Than Enhancing Adhesion; Understanding How Insects Control Adhesion & Release May Have Broader Implications

Geckos, tree frogs, spiders, and insects all share a special skill - they can walk up vertical surfaces and even upside down using adhesive pads on their feet. But geckos have “dry” feet, while insects have “wet” feet. Scientists have assumed that the two groups use different mechanisms to keep their feet firmly attached to a surface, but new research from David Labonte and Walter Federle, Ph.D., in the University of Cambridge's Department of Zoology provides evidence that this is not actually the case. "It has generally been assumed that the fluid on their feet must be involved in helping insects like stick insects adhere to a surface by capillary and viscous forces, in the same way that a beer glass will stick to a glass table if it's wet on the bottom," explains Labonte, lead author of the study published online on September 10, 2015 in Soft Matter, from the Royal Society of Chemistry, "but our research shows that the fluid is likely used for something else entirely; it may even help insects unstick their feet." The Soft Matter article is titled “'Rate-Dependence of 'Wet' Biological Adhesives and the Function of the Pad Secretion in Insects.” By measuring how much force was required to detach the foot of a stick insect from a glass plate at different speeds and applying the theory of fracture mechanics, Labonte and Dr. Federle found that only a “dry” contact model could explain the data. They also carried out a comparison of the sticking performance of wet and dry adhesive pads, which revealed that there is a striking lack of differences between the two, contrary to previous opinion.Insects and geckos need to walk up vertical surfaces and even upside down in order to get to the places where they feed and to escape from predators.

High-Arctic Butterflies Shrink with Rising Temperatures; Metabolic Rate Increases, Outstripping Feeding Capacity and Leading to Smaller Body Size

New research shows that butterflies in Greenland have become smaller in response to increasing temperatures due to climate change. It has often been demonstrated that the ongoing rapid climate change in the Arctic region is causing substantial change to Arctic ecosystems. Now, Danish researchers demonstrate that a warmer Greenland could be bad for its butterflies, which are becoming smaller under warmer summers. Researchers from Aarhus University in Denmark have measured wing length of nearly 4,500 individuals collected annually between 1996 and 2013 from Zackenberg Research Station in Northeast Greenland, and found that wing length has decreased significantly in response to warmer summers and at the same rate for both species investigated. "Our studies show that males and females follow the same pattern and it is similar in two different species, which suggests that climate plays an important role in determining the body size of butterflies in Northeast Greenland," says Senior Scientist Toke T. Hoye, Ph.D., Aarhus Institute of Advanced Studies, Aarhus University. Only very few field studies have been able to follow changes in the body size of the same species over a period during which the climate has changed and this is the longest-known time series on body size variation in butterflies, of which the scientists are aware. Body size change in response to rising temperature is an anticipated response to climate change, but few studies have actually demonstrated it in the field. The response can go both ways; for some animal species, a longer feeding season results in increased body size, and for others, the changes in metabolism cause a net loss of energy which reduces the body size.

Mad Cow Disease Changed Diet of Spain’s Galician Wolf; Following Disease-Related EU Carcass Disposal Regulations, Wolves Moved from Primarily Feeding on Carrion to Preying More on Live Animals

The Creutzfeldt-Jakob prion-caused disease crisis in Europe was a turning point for the diet of the Galician wolf in Spain, which, until the year 2000, had primarily fed on the carrion of domestic animals. A new study shows that, after European health regulations made it illegal to abandon dead livestock, wolves started to consume more wild boars, roe deer, and wild ponies, and also began to attack more cattle ranches when faced with food shortages in certain areas. With the arrival of bovine spongiform encephalopathy - commonly known as mad cow disease - in Europe, the European Community had to enforce a number of laws in the year 2000 in order to prevent the disease from spreading. Among other things, it became illegal to abandon the carcasses of ruminants that had died on farms; up until then, this had been an important food source for wolves. From then on, having been adopted by every European country, this measure began to affect a number of scavenger species, especially the vultures that lived on the Iberian Peninsula. But they weren't the only victims; the Iberian wolf (Canis lupus signatus) was also affected. A team of researchers has analyzed the dietary evolution of Galician canines by examining two time periods: before the European law was established (from the '70s up to the year 2000) and afterwards (from 2003 to 2008). Besides this legislation, a combination of other changes also affected the wolves, such as reductions in the quantity of livestock, rural depopulation, and the reforestation of agricultural land, which boosted the number of wild ungulates. The new study, published in the October 2015 issue of Environmental Management, indicates two very different dietary patterns for the two time periods.

2015 Nobel Prize in Chemistry Awarded for Mechanistic Studies of DNA Repair; Tomas Lindahl, Paul Modrich, & Aziz Sancar Share Award

On Wednesday, October 7, the Royal Swedish Academy of Sciences announced that it had decided to award the Nobel Prize in Chemistry for 2015 to Tomas Lindahl (Sweden, UK), Paul Modrich (USA) and Aziz Sancar (Turkey, USA) for having mapped, at a molecular level, how cells repair damaged DNA and safeguard the genetic information. Their work has provided fundamental knowledge of how a living cell functions and is, for instance, used for the development of new cancer treatments. The monetary prize of $970,000 will be shared equally amongst the three new Nobel Laureates. Each day our DNA is damaged by UV radiation, free radicals, and other carcinogenic substances, but even without such external attacks, a DNA molecule is inherently unstable. Thousands of spontaneous changes to a cell’s genome occur on a daily basis. Furthermore, defects can also arise when DNA is copied during cell division, a process that occurs several million times every day in the human body. The reason our genetic material does not disintegrate into complete chemical chaos is that a host of molecular systems continuously monitor and repair DNA. The Nobel Prize in Chemistry 2015 awards three pioneering scientists who have mapped how several of these repair systems function at a detailed molecular level. In the early 1970s, scientists believed that DNA was an extremely stable molecule, but Tomas Lindahl, Ph.D., demonstrated that DNA decays at a rate that ought to have made the development of life on Earth impossible. This insight led him to discover a molecular machinery, base excision repair, which constantly counteracts the collapse of our DNA. Aziz Sancar, Ph.D., has mapped nucleotide excision repair, the mechanism that cells use to repair UV damage to DNA. People born with defects in this repair system will develop skin cancer if they are exposed to sunlight.

October 6th

Giraffe Neck Evolution Traced to Two Key Stages of Lengthening in a Single Vertebra (C3); the Two Lengthenings Took Place 6 Million Years Apart and in Different Directions

Scientists have long theorized that the long neck of modern-day giraffes evolved to enable them to find more vegetation or to develop a specialized method of fighting. A new study of fossil cervical vertebrae reveals the evolution likely occurred in several stages as one of the animal's neck vertebrae stretched first toward the head and then toward the tail a few million years later. The study's authors say the research shows, for the first time, the specifics of the evolutionary transformation in extinct species within the giraffe family. "It's interesting to note that that the lengthening was not consistent," said Dr. Nikos Solounias, a giraffe anatomy expert and paleontologist at the New York Institute of Technology (NYIT) College of Osteopathic Medicine. "First, only the front portion of the C3 vertebra lengthened in one group of species. The second stage was the elongation of the back portion of the C3 neck vertebra. The modern giraffe is the only species that underwent both stages, which is why it has a remarkably long neck."The study, which includes a computational tracking model of the evolutionary elongation, was published online on October 7, 2015 in an open-access article in the journal Royal Society Open Science. The article is titled "Fossil Evidence and Stages of Elongation of the Giraffa camelopardalis Neck." Dr. Solounias and Melinda Danowitz, a medical student in the school's Academic Medicine Scholars program, studied 71 fossils of nine extinct and two living species in the giraffe family. The bones, discovered in the late 1800s and early 1900s, were housed at museums around the world, including ones in England, Austria, Germany, Sweden, Kenya, and Greece. "We also found that the most primitive giraffe already started off with a slightly elongated neck," said Danowitz.

Downregulation of KLK4 Gene Detected in East Asians; May Contribute to Specific Dental Traits and Eczema Resistance Found in Asians

Dr. Susana Seixas of the Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal, and colleagues have found key differences in a suite of genes important for skin and bone development that may have bestowed specific advantages amongst Asians. The new research was published online on September 29, 2015 in Molecular Biology and Evolution. The article is titled “Adaptive Evolution Favoring KLK4 Downregulation in East-Asians.” The researchers focused on the human kallikrein cluster (KLK), a suite of fifteen genes clustered on the long arm of chromosome 19 that play a key role in human adaptation and reproductive biology. The genes function as molecular scissors called serine proteases, which target and clip other proteins involved in semen function, teeth development, skin and blood pressure maintenance, and even cancer. The team undertook a large study to identify 1,419 DNA differences in the KLK genomic cluster amongst Eastern Asian (Han Chinese and Japanese), African, and European populations by using new DNA data from the recently completed 1000 Genomes project. The most striking differences were narrowed down to two regions near the KLK4 gene, which were found to severely hamper the activity of KLK4 only in Asian populations. This KLK4 downregulation may contribute to dental traits typically found in Asians and be important in controlling skin conditions like eczema, which is much more prevalent in northern Europe than in Asia. "We further predict many effects related to male biology and other physiological functions with possible outcomes in human complex diseases, said Dr. Seixas.

Knees Evolved First in Spiders, by Duplication of “dachshund” Gene

Dr. Nikola-Michael Prpic and colleagues from Abteilung für Entwicklungsbiologie, GZMB Ernst-Caspari-Haus, Johann-Friedrich-Blumenbach-Institut für Zoologie und Anthropologie, Georg-August-Universität, Göttingen, Germany, have identified the driving force behind the evolution of a leg novelty first found in spiders: knees. They report their findings in a new study published online on October 6, 2015 in Molecular Biology and Evolution, The article is titled “Neofunctionalisation of a Duplicate dachshund Gene Underlies the Evolution of a Novel Leg Segment in Arachnids.” With eight legs and seven joints on each---that's a lot for a spider to coordinate just to take a single step. Dr. Prpic's research team homed in on a gene called dachshund (dac). This gene was first discovered in fruit flies, and humorously named for the missing leg segments and shortened legs that result from dac mutant flies. But arachnids are different from flies and other arthropods, possessing a second dac gene. And the second dac gene (dac2) is expressed only in the kneecap, or patella, during spider development. When the research group used RNA interference experiments to specifically deactivate dac2, the kneecap fuses with the tibia to form a single leg segment. The force behind knees first appearing on the spider evolutionary scene was a result of ancient gene duplication in the original dac gene that, over time, evolved into an entirely new function and way of unique way of walking about for spiders. "Species constantly adapt and evolve by inventing new body features," said Dr. Prpic. "Our work shows how a gene can be duplicated and then used during evolution to invent a new morphological feature."

Emmanuelle Charpentier and Jennifer Doudna Share $500,000 Gruber Genetics Prize for Landmark Discovery of RNA-Guided CRISPR/Cas9 Editing System; Prize to Be Awarded Friday, October 9, at ASHG Annual Meeting

The 2015 Gruber Genetics Prize will be awarded this year to microbiologist Emmanuelle Charpentier, Ph.D., of the Helmholtz Centre for Infection Research in Braunschweig, Germany, and biochemist Jennifer Doudna, Ph.D., of the University of California, Berkeley. These two eminent scientists are being recognized for their joint creation of a revolutionary gene-editing technology known as CRISPR/Cas9, which functions as a molecular scissor, generating double-stranded cuts in targeted DNA molecules with exceptional precision. The technology is being used around the world to advance biological research and to engineer genes for developing powerful new therapies for a wide range of human diseases, as well as new biofuels and agricultural products. The award will be presented to Dr. Charpentier and Dr. Doudna in Baltimore, Maryland, on Friday, October 9, during the 2015 annual meeting of the American Society of Human Genetics (ASHG). “The discovery of the CRISPR/Cas9 cellular defense system has transformed molecular genetics,” said Utpal Banerjee, Ph.D., a member of the Selection Advisory Board to the Prize. Dr. Banerjee is Professor and Chair of the Department of Molecular, Cell, and Developmental Biology at UCLA. He did his post-doctoral fellowship in the laboratory of the renowned Seymour Benzer, Ph.D. “We now have a quick and highly accurate technology for deleting or adding specific pieces of DNA, an advance with wide-ranging implications for both basic science and clinical medicine,” Dr. Banerjee added. Dr. Charpentier and Dr. Doudna began their collaboration in 2011 after meeting at a scientific conference in Puerto Rico. Both had been trying to unlock the molecular mysteries of the CRISPR systems, an unusual repeating sequence of DNA that enables bacteria to mount a successful defense against viral invaders.

Two Young Women Geneticists Receive 2016 Rosalind Franklin Young Investigator Award; Mary-Claire King Comments

The Genetics Society of America (GSA), the American Society for Human Genetics (ASHG), and The Gruber Foundatio recently announced that Maria Barna, Ph.D., of Stanford University; and Carolyn McBride (photo), Ph.D., of Princeton University, are the 2016 recipients of the Rosalind Franklin Young Investigator Award. The Rosalind Franklin Young Investigator Award is funded by The Gruber Foundation and is awarded every three years to two women geneticists at the beginning of their independent research careers. Winners are selected by a joint committee appointed by the GSA and the ASHG from nominees from around the world. The award recognizes outstanding genetics research in two categories: mammalian genetics, including human genetics; and non-mammalian genetics. Each winner will receive a $75,000 award to be used as she chooses for her research. “The Rosalind Franklin Award celebrates the accomplishments of the next generation of young women scientists, who are following the path laid down by our fore-mothers,” said Mary-Claire King, Ph.D., Chair of the Rosalind Franklin Award committee and Professor of Genome Sciences and Medicine (Medical Genetics) at the University of Washington. Dr. King is world-famous for her seminal research into the genetics of breast cancer, which largely enabled the identification of both the BRCA1 and BRCA2 breast cancer genes. “Reading the creative work of these remarkable young women is a great joy for the committee. We congratulate the winners and send our very best wishes for continued success to all the nominees.” Dr. Barna, the 2016 recipient in human and mammalian genetics, uses mouse genetics to understand how ribosomes process information to create proteins for different types of cells and tissues. Dr. Barna received her bachelor’s degree in anthropology from New York University and her Ph.D.