Case Western Reserve Theorist Develops Incomparable Model that Unifies Physics, Chemistry, and Biology Continue reading
Numerous infant studies indicate environmental knowledge is present soon after birth Continue reading
Two million-year-old bones belonging to a creature with both apelike and human traits provide the clearest evidence of evolution’s first major step toward modern humans — findings some are calling a potential game-changer.
An analysis of the bones found in South Africa suggests Australopithecus sediba is the most likely candidate to be the ancestor of humans, said lead researcher Lee R. Berger of the University of Witwatersrand in South Africa.
The fossils, belonging to a male child and an adult female, show a novel combination of features, almost as though nature were experimenting. Some resemble pre-human creatures while others suggest the genus Homo, which includes Homo sapiens, modern people.
“It’s as if evolution is caught in one vital moment, a stop-action snapshot of evolution in action,” said Richard Potts, director of the human origins program at the Smithsonian Institution. He was not among the team, led by South African scientists, whose research was published online Thursday in the journal Science. Continue reading
New research raises troubling concerns about the use of aggressive drug therapies to treat a wide range of diseases such as MRSA, C. difficile, malaria, and even cancer.
“The universally accepted strategy of aggressive medication to kill all targeted disease pathogens has the problematic consequence of giving any drug-resistant disease pathogens that are present the greatest possible evolutionary advantage,” says Troy Day, one of the paper’s co-authors and Canada Research Chair in Mathematical Biology at Queen’s.
The researchers note that while the first aim of a drug treatment program should be to make and keep a patient healthy, the patient’s immune system also has to be allowed to work.
They suggest several strategies Continue reading
“Man is but a worm” was the title of a famous caricature of Darwin’s ideas in Victorian England. Now, 120 years later, a molecular analysis of mysterious marine creatures unexpectedly reveals our cousins as worms, indeed.
An international team of researchers, including a neuroscientist from the University of Florida, has produced more evidence that people have a close evolutionary connection with tiny, flatworm-like organisms scientifically known as “Acoelomorphs.”
The research in the Thursday (Feb. 10) issue of Nature offers insights into brain development and human diseases, possibly shedding light on animal models used to study development of nerve cells and complex neurodegenerative diseases such as Alzheimer’s and Parkinson’s.
“It was like looking under a rock and finding something unexpected,” said Leonid L. Moroz, Ph.D., a professor in the department of neuroscience with the UF College of Medicine. “We’ve known there were very unusual twists in the evolution of the complex brains, but this suggests the independent evolution of complex brains in our lineage versus invertebrates, for example, in lineages leading to the octopus or the honeybee.”
The latest research indicates that of the five animal phyla, the highest classification in our evolutionary neighborhood, four contain worms. But none are anatomically simpler than “acoels,” which have no brains or centralized nervous systems. Less than a few millimeters in size, acoels are little more than tiny bags of cells that breathe through their skin and digest food by surrounding it.
Comparing extensive genome-wide data, mitochondrial genes and tiny signaling nucleic acids called microRNAs, the researchers hailing from six countries determined a strong possibility that acoels and their kin are “sisters” to another peculiar type of marine worm from northern seas, called Xenoturbella.
From there, like playing “Six Degrees of Kevin Bacon,” the branches continue to humans.
“If you looked at one of these creatures you would say, ‘what is all of this excitement about a worm?'” said Richard G. Northcutt, Ph.D., a professor of neurosciences at Scripps Institution of Oceanography, who was not involved in the study. “These are tiny animals that have almost no anatomy, which presents very little for scientists to compare them with. But through genetics, if the analysis is correct – and time will tell if it is – the study has taken a very bothersome group that scientists are not sure what to do with and says it is related to vertebrates, ourselves and echinoderms (such as starfish).
“The significance of the research is it gives us a better understanding of how animals are related and, by inference, a better understanding of the history of the animals leading to humans,” Northcutt said.
Scientists used high-throughput computational tools to reconstruct deep evolutionary relationships, apparently confirming suspicions that three lineages of marine worms and vertebrates are part of a common evolutionary line called “deuterostomes,” which share a common ancestor.
“The early evolution of lineages leading to vertebrates, sea stars and acorn worms is much more complex than most people expect because it involves not just gene gain, but enormous gene loss,” said Moroz, who is affiliated with the Whitney Laboratory for Marine Bioscience and UF’s McKnight Brain Institute. “An alternative, yet unlikely, scenario would be that our common ancestor had a central nervous system, and then just lost it, still remaining a free living organism.
Understanding the complex cellular rearrangements and the origin of animal innovations, such as the brain, is critically important for understanding human development and disease, Moroz said.
“We need to be able to interpret molecular events in the medical field,” he said. “Is what’s happening in different lineages of neuronal and stem cells, for example, completely new, or is it reflecting something that is in the arrays of ancestral toolkits preserved over more than 550 million years of our evolutionary history? Working with models of human disease, you really need to be sure.”
DETROIT – Scientists now have physical proof of how species evolve and the fittest survive, after a 21-year study in which they documented the evolution of single-celled E. coli bacteria over 40,000 generations.
Lenski’s team periodically froze bacteria for later study, and technology has since developed to allow complete genetic sequencing. By the 20,000-generation midpoint, researchers discovered 45 mutations among surviving cells in the bottled bacteria.
Those mutations, according to
The results “beautifully emphasise the succession of mutational events that allowed these organisms to climb toward higher and higher efficiency in their environment”, noted
Lenski’s long-running experiment itself is uniquely suited to answer some critical questions — such as whether rates of change in a bacteria’s genome move in tandem with its fitness to survive.
A mutation involved in DNA metabolism arose around generation 26,000, causing the mutation rate everywhere else in the genome to increase dramatically.
The number of mutations jumped to 653 by generation 40,000, but researchers surmise that most of the late-evolving mutations were not helpful to the bacteria, said an MSU release.
“So what we learn here can help us better understand the course of these diseases.”
The paper involved collaboration with scientists from South Korea as well as
The findings were published in Nature.
BEVERLY HILLS – In the male body, testosterone is the most important sex hormone. Testosterone is responsible for development of male characteristics such as body and facial hair, muscle growth and strength, and a deep voice. Normal levels of testosterone also influence the production of sperm, promote sexual function and promote sex drive.
We now know that some men’s bodies do not make enough testosterone. These men may experience uncomfortable and sometimes distressing symptoms. The U.S. Food and Drug Administration (FDA) estimates that 4 to 5 million American men may suffer from low testosterone, but only 5 percent are currently treated.
SYMPTOMS OF LOW TESTOSTERONE
As men get older, the ability to produce testosterone declines. This decrease in testosterone production is sometimes referred to as andropause or “male menopause.” If testosterone levels fall below the normal range some typical symptoms may include:
· Low sex drive
· Erectile dysfunction (
· Increased irritability or depression
· Reduced muscle mass and strength
· Inability to concentrate
· Decreased bone density; osteoporosis
In addition to age-related low testosterone, there are certain medical conditions that can cause low testosterone. These medical conditions can begin in youth or in adulthood, and can affect testosterone levels throughout a man’s life. Some of these conditions are associated with the testicles, pituitary gland and/or hypothalamus (a part of the brain that controls many of the body’s glands). Occasionally, the problem can be genetic.
In younger men, low testosterone production may reduce the development of body and facial hair. Muscle mass and genitals may not develop normally, and younger men’s voices may fail to deepen.
BE SURE TO GET SCREENED
If you experience symptoms associated with low testosterone, you may want to ask your doctor about getting your testosterone levels checked. Your primary care physician can check your testosterone levels with a simple blood test and treat you if you have low testosterone. You might also ask your primary care physician about a referral to an endocrinologist or urologist who specializes in treating conditions such as low testosterone.
Regular checkups and age-appropriate screenings can improve your health and extend your life. Consider adding regular screening for low testosterone to other screenings as part of your checkup.
IF YOU HAVE LOW TESTOSTERONE
If you do have low testosterone, the good news is that the condition is treatable. There are several FDA-approved testosterone replacement therapies, including:
* Clear gel that you rub on your arm every morning
Talk to your doctor about which option may be best for you.
PORTLAND – By resurrecting ancient proteins, University of Oregon researchers have found that evolution is irreversible, and can only go forward.
The University of Oregon research team found that evolution can never go backwards, because the paths to the genes once present in our ancestors are forever blocked.
The team used computational reconstruction of ancestral gene sequences, DNA synthesis, protein engineering and X-ray crystallography to resurrect and manipulate the gene for a key hormone receptor as it existed in our earliest vertebrate ancestors more than 400 million years ago.
They found that over a rapid period of time, five random mutations made subtle modifications in the protein’s structure that were utterly incompatible with the receptor’s primordial form.
“We solved those problems by studying the problem at the molecular level, where we can resurrect ancestral proteins as they existed long ago and use molecular manipulations to dissect the evolutionary process in both forward and reverse directions,” he said.
In previous work,
They then identified seven ancient mutations that together caused the receptor to evolve its new specificity for cortisol.
So they resurrected the GR as it existed soon after cortisol specificity first evolved-in the common ancestor of humans and all other vertebrates with bones – and then reversed the seven key mutations by manipulating its DNA sequence.
“We expected to get a promiscuous receptor just like the GR’s ancestor, but instead we got a completely dead, non-functional protein,”
“Apparently other mutations that occurred during early GR evolution acted as a sort of evolutionary ratchet, rendering the protein unable to tolerate the ancestral features that had existed just a short time earlier,” he added.