SciTech Briefs

Past humans may have spent 10,000 years on ice bridge

Recent genetic and environmental evidence suggests that early humans may have spent around 10,000 years on the Bering land bridge before moving into the Americas.Most paleontologists assumed the Bering land bridge had been an inhospitable tundra steppe and that humans would not have stayed long there. However, drilled sediment from under the Bering sea indicates that the land bridge may have had shrubs, or even trees. Other evidence around this time indicates that ice sheets covered much of America, thus isolating the land bridge. Genetic analysis also supports the hypothesis. By looking at mitochondrial DNA, which is only passed down through the mother, it was determined that Native Americans became a genetically distinct population around 25,000 years ago but did not actually migrate into the Americas until around 15,000 years ago.

Source: Science Daily

U.K. proposes legislation to allow embryo donations

The U.K. government has proposed legislation that may allow the DNA of a healthy donor to be implanted into an embryo of two other parents. The procedure would allow women who have mitochondrial diseases to have healthy children. In the procedure, the mitochondria in the embryo is swapped with a healthy donor’s mitochondria; this process causes some mitochondrial DNA to also be transferred to the embryo.This form of alteration could be passed down through generations. Currently, U.K. legislature forbids the genetic alteration of human eggs or embryos. The U.K. has been evaluating the medical and social issues surrounding the procedures since 2011, when scientists claimed the technique was ready for human trials.

Source: Science Insider

Eating device may help patients who have hand tremors

A new study released by the University of Michigan shows that a hand tool can help patients overcome tremors and eat normally. The study included 15 patients with moderate-to-severe tremors and showed that the device — developed by Anupam Pathak, CEO of San Francisco-based startup firm Lift Labs — could stabilize the tremors enough for patients to be able to keep a spoon and fork stable enough to eat. Patients rated the device’s effectiveness by using a standard tremor rating and by analyzing digital readings of the spoon’s movement.

The tool utilizes tiny sensors that can detect movement from all angles and then respond with a quick countermovement.

Source: Science Daily

Prenatal nicotine exposure shown to lead to ADHD

A new study out of Florida State University found evidence that a prenatal exposure to nicotine could affect multiple future generations. The researchers, professors Pradeep G. Bhide and Jinmin Zhu, suggest that nicotine exposure can cause epigenetic changes — changes that affect parts of one’s DNA, such as turning on or off certain regions. Prior studies suggested that smoking during pregnancy led to a 40 percent increase likelihood of Attention Deficit Hyperactivity Disorder (ADHD) cases.

To see if something was happening at the genetic level, Bhide and Zhu exposed pregnant mice to nicotine. In their multigenerational study, they found that changes occurring in the grandparent’s genes were being passed on to offspring. However, many future studies are needed before any sort of causality between the two is determined.

Source: Science Daily

Mysterious polio-like illness found in five children

At least five children in California have been suffering from a virus that causes polio-like symptoms, including limb paralysis and problems with breathing. In all of these cases, the children did not respond to treatments and their paralysis appears to be permanent. The children do not have polio, since they were all vaccinated against it. Doctors believe that the cause of the symptoms may be enterovirus-68, which was first detected in California over 50 years ago. Enterovirus-68 has been confirmed in two of the cases. Other viruses which are known to have paralysis as a symptom are West Nile, echoviruses, and adenoviruses.
Researchers say that the problem is not endemic and parents should be aware, but not alarmed.

Source: NPR

Older paternal age linked to likelihood of ADHD in kids

A recent study published in JAMA Psychiatry has shown that children born to fathers over the age of 45 are three times more likely to develop autism and 13 times more likely to have Attention Deficit Hyperactivity Disorder (ADHD) than children born to fathers 20–24 years of age. The researchers looked at millions of parent-child relationships in Sweden between 1973 and 2001. They focused specifically on relationships with siblings; using related individuals takes out environmental factors. Previous studies also linked older fathers with increases in substance abuse and schizophrenia among their children.

Source: NPR