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Tag: "hypothesis" at biology news

Scientists track stealth DNA elements in primate evolution

...t of AluYa5, and to formulate the "stealth driver" hypothesis for the evolution of these Alu elements. "In contrast to 'master' genes, 'stealth drivers' are not responsible for generating the majority of new Alu copies, but rather for maintaining genomic retrotransposition capacity over extended periods of tim...

USC researchers determine mechanism of action of chemotherapy drug

..., adding that it also may "provide support for the hypothesis that agents that disrupt metabolism and increase intracellular zinc levels have potential applications as anticancer therapeutics." ...

Carnegie Mellon University research reveals how cells process large genes

...ing humans, and the Lopez team is now testing this hypothesis experimentally. "The striking evolutionary conservation of ratchetting points suggests that recursive splicing provides specific advantages for large introns," Lopez said. "One possibility is that recursive splicing prevents the generation of long R...

Reversal of role for a viral protein associated with the development of lymphoma

...ing humans, and the Lopez team is now testing this hypothesis experimentally. "The striking evolutionary conservation of ratchetting points suggests that recursive splicing provides specific advantages for large introns," Lopez said. "One possibility is that recursive splicing prevents the generation of long R...

Scientists devise way to measure RNA synthesis on the fly in a live cell

...explain the motion of galaxies. "They proposed the hypothesis that the motion of galaxies is affected by the presence of invisible matter called 'dark matter,'" Cluzel said. In recent years, astronomers have rushed to design experiments that might help them determine what dark matter is made of. "RNA molecules...

Chemical 'band-aid' prevents heart failure in mice with muscular dystrophy

... of dystrophin on individual cardiac myocytes. Our hypothesis was that stretching created small tears or holes in the myocyte membrane, which allowed calcium ions to get inside the cell. When calcium floods a cell, it triggers a hyper-contraction, which causes the cell to roll into a little ball and die." To t...

Discovery of T-cell 'traffic control' boosts new drug promise

... slow the autoimmune response that occurs in MS, a hypothesis recently confirmed in phase 2 clinical trials, he says. Such drugs do not interfere with essential protective immune function since bacterial proteins that normally trigger immune defense do so when they enter lymph nodes -- "where the T cells are e...

Microbe has huge role in ocean life, carbon cycle

...riving for a billion years or more. One scientific hypothesis holds that natural selection acts to reduce genome size because of the metabolic burden of replicating "junk" DNA with no adaptive value - SAR11 supports that theory. Researchers are particularly interested in SAR11, Giovannoni said, because of the ...

Ants, not evil spirits, create devil's gardens in the Amazon rainforest, study finds

... offered to explain why devil's gardens occur. One hypothesis is that D. hirsuta trees release toxic secretions that kill competing plants--a process botanists call allelopathy. Others argue that devil's garden ants are responsible for controlling vegetation, either by extensive pruning or poisoning. "The idea ...

Ancient DNA confirms single origin of Malagasy primates

...of subfossil lemurs adds additional support to the hypothesis that non-human primates colonized Madagascar only once," Yoder said. "However, the limited taxonomic success of our study leaves open the possibility that data from additional taxa will overturn this increasingly robust hypothesis." Yoder said the r...

Stem cells bring fast direct improvement, without differentiation, in acute renal failure

...ls. These new results "challenge the most popular hypothesis of how stem cells work in kidney protection and repair, which holds that administered stem cells enter an injured organ where they differentiate into those cells that have been destroyed, and thus replace them both anatomically and functionally," Wes...

Variant prion protein causes infection but no symptoms

...ch? What if only small clumps are toxic?" If this hypothesis proves correct, Dr. Chesebro says, the ongoing research could eventually alter scientists' views on preventing prion diseases, shifting emphasis away from stopping the production of prion protein clumps and toward preventing interactions with prion p...

India's smoking gun: Dino-killing eruptions

...aused a deadly global climate shift. "Our working hypothesis is that the majority of the total volume of lava might have been erupted in only a few major events spread over only a small fraction of millennia," said Anne-Lise Chenet of the Laboratoire de Paleomagnetisme, Institut de Physique du Globe de Paris (...

Birds and bats sow tropical seeds

...died. Howe suspects that evidence will support the hypothesis that birds and bats transport a rich mix of tree seeds, including the more enduring deep forest species. "It's a way of providing connection between existing, isolated trees, remnants and fragments and large tracts growing along rivers in rain fores...

Weapon performance determines mating success in the collared lizard

... males function as a weapon in fights, to test the hypothesis that weapon performance (i.e., bite force) is a be...that bigger is always better, and they support the hypothesis that weapon performance, which is likely to directly influence fight outcomes, has far stronger effe...

Prenatal exposure to famine increases risk of schizophrenia

...hina, and colleagues conducted a study to test the hypothesis that prenatal exposure to famine would increase the rate of schizophrenia in adult life by examining people who lived through a massive famine in China from 1959-1961. The risk of schizophrenia was examined in the Wuhu region of Anhui, one of the mos...

New antibody shows promise as cure for anthrax

...s, which might both be part of the full story. One hypothesis is that the antitoxin somehow neutralizes anthrax bacteria and prevents it from replicating. The other looks to innate immunity, theorizing that since the high-affinity antibody clears the body of the deadly toxin, it allows the body's initial immune...

Prostate cancer uses Wnt signaling proteins to promote growth of bone tumors

...at both processes are going on," Keller says. "Our hypothesis is that prostate cancer cells first induce more bone resorption to help the invading cells become established in bone. But then there's a switch to increased bone production. Although we don't know the exact mechanism responsible for the switch, we k...

Getting an evolutionary handle on life after reproduction

... to the fitness of their offspring or relatives, a hypothesis called the "grandmother effect." Though many mammals, including lions and baboons, rear dependent young and operate within complex social groups, studies have found no evidence of a granny effect, and females mostly live just long enough to care for ...

Sickle cell disease corrected in human models using stem cell-based gene therapy

..., they made normal hemoglobin. "This proved our hypothesis that you can simultaneously add one function and delete another in the same cell and obtain synergistic genetic modifications within a single cell," said Selda Samakoglu, PhD, a member of Dr. Sadelain's laboratory and the study's first author. "In th...

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