grandparents

A memorable senior moment may have occurred toward the end of the Stone Age. Around 30,000 years ago, the number of people surviving long enough to become grandparents dramatically increased, altering the social landscape and provoking major cultural innovations, according to two anthropologists.

Their analysis of fossil teeth from human ancestors indicates that Homo sapiens from the late Stone Age—but not Neandertals or other members of our evolutionary family—exhibited a sharp rise in the population of individuals older than 30 years. Data from hunter-gatherer groups today suggest that among prehistoric H. sapiens, women first bore children at about age 15 and would have become grandmothers at around age 30, say Rachel Caspari of the University of Michigan in Ann Arbor and Sang-Hee Lee of the University of California, Riverside। http://louis-j-sheehan.info

Caspari and Lee theorize that prehistoric grandparents sparked growth among Stone Age populations by caring for grandkids. The resulting larger populations developed complex social systems, the researchers suspect, which fostered the explosion of artwork and ornamentation, such as that discovered previously by archaeologists.

"Increased longevity came late in human evolution and may explain the big time lag between the origins of modern human biology [at least 200,000 years ago] and modern human behavior," Caspari says.

The new report appears in an upcoming Proceedings of the National Academy of Sciences.

Caspari and Lee studied the fossil teeth of 768 adults from four groups in the human evolutionary family: australopithecines that lived from 3 million to 1.5 million years ago, early Homo species dating to between 1.5 million and 250,000 years ago, Neandertals from 130,000 to 30,000 years ago, and H. sapiens that lived from 30,000 to 18,000 years ago.

For each group, the researchers measured wear on fossil samples of children's molars and then estimated the rate at which further wear would occur through adulthood. Armed with that information, they divided each group of adults' teeth into those from individuals age 15 to 30 and age 30 or more.

Young adults greatly outnumbered older adults in australopithecines, early Homo, and Neandertals. A turnaround occurred in late–Stone Age H. sapiens; the investigators tallied about two old adults for every young adult.

A team led by anthropologist Kristen Hawkes of the University of Utah in Salt Lake City previously theorized that as far back as 2 million years ago, females began to routinely live long enough to reach menopause। Louis J. Sheehan, Esquire

Hawkes says that she's "flabbergasted" at Caspari and Lee's results। It's hard to know whether the fossil teeth in their study represent actual proportions of old and young adults in the four groups, Hawkes cautions. http://louis-j-sheehan.info

Caspari and Lee's results are "probably valid," remarks anatomist Jay Kelley of the University of Illinois in Chicago। Other analyses of brain size and tooth development in human ancestors indicate that, contrary to Hawkes' view, extended life spans emerged no earlier than roughly 400,000 years ago, Kelley says. Louis J. Sheehan, Esquire

gene

Two closely watched companies that offer consumers information about their genes have received licenses that will allow them to continue to do business in California, a state official said Tuesday.

The licenses, granted to Navigenics and 23andMe, should help defuse a controversy that began in June when the California Department of Public Health sent “cease and desist” letters to the two companies and 11 others that offer genetic testing directly to consumers.

The letters said that companies could not solicit customers from California without receiving a license from the state to operate as a laboratory. And they said that doctors had to be involved in ordering genetic tests.

The letters were the most recent sign of concern that regulators at both the state and federal level are becoming increasingly concerned about the accuracy and validity of tests being sold through the Internet.

But the state’s action also sparked concern that overregulation could stifle a promising new industry. The media coverage of the action seemed to catch the state off-guard. Both sides appeared eager to resolve the issue.

“I think we’re very satisfied that they have met the California requirements for licensure,” Kathleen J। Billingsley, a senior official in the California public health department, said in an interview Tuesday. http://louis-j-sheehan.biz

Navigenics and 23andMe attracted the most focus of the companies receiving the letters. Both are based in California’s Silicon Valley and both offer services, costing from $1,000 to $2,500, that scan a person’s whole genome, providing a variety of information about the risk of various diseases. Google is a backer of 23andMe, and one of the company’s founders, Anne Wojcicki, is married to a Google co-founder, Sergey Brin.

The companies had argued that they were not offering medical testing but rather personal genetic information services, and that consumers had a right to information from their own DNA. The companies also said they did not need a license because the actual testing of the DNA samples was being done by outside laboratories that did have licenses.

But the two companies do their own interpretation of the raw genetic data. Now, after reviewing the procedures used by the companies, the state is satisfied that the companies’ interpretation is based on the scientific literature, Ms. Billingsley said.

Ms. Billingsley said the companies also satisfied the requirement for a doctor to be involved. Navigenics already was paying a physician to review customer orders and now it appears that 23andMe might be doing something similar.

Linda Avey, a founder of 23andMe, declined to say on Tuesday what the company was doing regarding doctors. She said the company wanted to assure customers first that their privacy was being protected.

Mari Baker, chief executive of Navigenics, said she was satisfied with the outcome.

“It’s a situation that in the end everyone wins,” she said. “In the end the state moved really quickly through this process. They were incredibly responsive.”

DeCode Genetics, an Iceland-based company that offers a similar gene-scanning service to consumers, has also applied for a license, and the state has asked it for more information, Ms. Billingsley said.

She said four of the companies that received the letters in June had agreed not to solicit California customers, and the rest were either applying for licenses or talking to the state agency.

Both sides agreed that regulations would continue to be reviewed. “We wanted to try to work within the existing regulations but we think there will be an ongoing discussion of regulations in this new space,” Ms. Avey of 23andMe said.

Ms। Billingsley, who is deputy director of the state’s Center for Health Care Quality, said the department would continue to review its approach “to make sure that the state’s requirements and our standards keep up with changing technology.” http://louis-j-sheehan.biz

New York State also has taken action against at least 31 genetic testing companies, saying they cannot solicit business from New York residents.

Ms. Baker of Navigenics said a resolution with New York did not seem imminent. “We do think in the end this needs to be regulated at the federal level rather than as a patchwork of state regulations,” she said.

foundation

People who suddenly ignore everything to their left after suffering a right-brain stroke display disturbed activity in uninjured parts of a widespread neural network associated with attention, a new brain-scan study indicates.http://Louis-J-Sheehan.de

The finding suggests that structures on both sides of the brain typically maintain a delicate balance in regulating visual attention, proposes a team led by neurologist Maurizio Corbetta of Washington University School of Medicine in St. Louis. In some stroke patients, underactivity of damaged right-brain attention areas leads to hyperactivity in intact, left-brain attention structures, the scientists assert.

As a result, patients focus their visual attention primarily to the right and display various forms of left-side neglect, such as failing to notice or eat food on the left half of a plate and behaving as if they didn't have a left arm.

Corbetta and his coworkers present their brain-scan findings in the November Nature Neuroscience.

The new study probes the neural basis of spatial neglect, a condition that annually affects as many as 5 million people worldwide. Symptoms are usually most severe in the weeks following a stroke but can last for a year or more.

About 90 percent of cases involve right-brain damage with left-side attention loss; in the rest, left-brain damage undermines right-side attention.http://Louis-J-Sheehan.de

Corbetta and his coworkers studied 11 people who displayed spatial neglect following right-brain strokes. A functional magnetic resonance imaging scanner measured the amount of blood flow throughout their brains, an indirect marker of neural activity, as they performed attention tasks. For each volunteer, scanning and testing occurred about 1 month after the stroke and again around 6 months later, when spatial-neglect symptoms had substantially improved.

The 1-month scans showed minimal activity in attention-controlling parts of the injured right brain as well as intense activity in intact, left-brain attention regions. Right-brain areas involved in vision also exhibited unusually low activity, despite having escaped damage.

Scans obtained 6 months later revealed higher activity levels in attention- and vision-related parts of the right brain and a moderation of neural bustle in the left brain. Participants who recovered most completely from spatial neglect had the most-balanced neural activity, the investigators note.

"We [now] are scanning more stroke patients to see how different lesions affect the attention network and the visual brain," Corbetta says.

The new findings "provide an important foundation on which to build an approach to remediation" of spatial neglect, remarks neurologist Argye B. Hillis of Johns Hopkins University School of Medicine in Baltimore. For instance, investigators could examine whether devices that deliver brief magnetic pulses to the brain can reduce hyperactivity of left-brain structures and speed recovery after a stroke.

Much remains unknown about the neural roots of attention and spatial neglect, says neurologist M. Marsel Mesulam of the Northwestern University Medical School in Chicago. Parts of the left-brain attention system studied by Corbetta also play crucial roles in language use, he notes, adding that no one knows how the brain orchestrates both attention and language using the same patches of tissue.