When pregnant, dominant female meerkats subject their subordinates to escalating aggression and temporary eviction causing them to become overly stressed and as a result infertile, a new study finds.
Organisms, including humans, all inherit DNA from generation to generation, what biologists call hard inheritance, because the nucleotide sequence of DNA is constant and only changes by rare random mutation as it is passed down the generations.
But there also is evidence, especially in plants, that non-genetic factors modifying the DNA can also be inherited. The modifications of the genetic material take the form of small chemical additions to one of the DNA bases and the alternative packaging of the DNA. These so-called epigenetic modifications are known to be important for turning genes on and off during the course of an organism's life, but their importance in controlling inheritance has been debated. Many biologists are skeptical of any form of soft inheritance, where the genetic material is not constant, believing that it is only genetic information - DNA -- that can be passed onto generations.
"To get to the issue of the more extreme variations of soft inheritance, it has to be determined whether the environment can induce an epigenetic change in an organism that can be inherited in subsequent generations. Certainly, nobody has shown that an epigenetically induced beneficial or adaptive change has been inherited. Mechanistically, there is no reason to discount epigenetic inheritance. The biochemical nuts and bolts are there to support it. The big questions to resolve are how many epigenetic changes are induced by the environment, what types of phenotypes result from these changes, and how many of these epigenetic changes are inherited."
Further proof that children require more time comes via a study to be published today in Developmental Science asserting that the fast pace expected by adults--both parents and educators--can be beyond chindren's perceptual abilities.
"We expect children to be adult-like, because of their proficiency on computers or because they display adult-like speech," he says, "so we give them instructions and get impatient when they can't understand what we tell them the first time. Children learn through repetition, at a pace suitable to the child, not to the curriculum. Once upon a time, kids controlled their own pace; now that pace is controlled by adults."
The same chemical in the body that is targeted by the drug ViagraÂ® also helps our brains "boot up" in the morning so we can process sights, sound, touch and other sensory information. The discovery could lead to a better understanding of major brain disorders, according to researchers from Wake Forest University School of Medicine.
"We expected to find that signals from the eye would be boosted by nitric oxide," said Godwin. "Instead, we found that nitric oxide reduced signals from the eyes, and enhanced the feedback from the cortex. The tiny molecule appears to allow the cortex to exert more control on how much information it receives from the thalamus."
Using advanced brain sensor technology developed at the University of Oregon, researchers have confirmed often-debated findings from 1992 that showed infants as young as six months know when an arithmetic solution is wrong.
Results of a new imaging study, supported in part by the National Institute on Drug Abuse (NIDA), National Institutes of Health, show that the nicotine received in just a few puffs of a cigarette can exert a force powerful enough to drive an individual to continue smoking. Researchers found that the amount of nicotine contained in just one puff of a cigarette can occupy about 30 percent of the brain's most common type of nicotine receptors, while three puffs of a cigarette can occupy about 70 percent of these receptors. When nearly all of the receptors are occupied (as a result of smoking at least 2 and one-half cigarettes), the smoker becomes satiated, or satisfied, for a time. Soon, however, this level of satiation wears off, driving the smoker to continue smoking throughout the day to satisfy cigarette cravings.
"Does Environment Influence Genes? Researcher Gives Hard Thoughts On Soft Inheritance
This news release is based on Richards' paper "Inherited epigenetic variation - revisiting soft inheritance" which is currently available (without subscription) as a pdf file here
John Latter / Jorolat