August 24, 2012 |
A study this week reported that older men pass on more new mutations to their offspring than do younger men, a fact that could help explain higher rates of disorders such as autism, schizophrenia and others in kids born of older fathers. The same week, another article by the same group calculated that the mutation rate in fathers doubles between age 20 and age 58. Why fathers more than mothers? Because many of these mistakes happen as cells divide, and as we get older the rate of errors rises.
March 3, 2011 |
Two studies released Wednesday by the journal Nature show that work remains before so-called induced pluripotent stem (iPS) cells are ready for use in laboratory studies or clinical therapies. iPS cells are body cells that are programmed to unwind back into an embryonic state. Like embryonic stem cells, they have potential to develop into any other type of cell in the body. But they don't reprogram perfectly, researchers are showing. About a month ago, a team at the Salk Institute showed that iPS cells hold on to "memory" of their past identity.
August 22, 2012 |
Men who become fathers later in life pass on more brand-new genetic mutations to their offspring, a study has found - probably contributing to disorders such as autism and schizophrenia in the next generation. The finding, published online Wednesday in the journal Nature , buttresses earlier observations that rates of autism and some other disorders are more prevalent in children born of older fathers, sometimes by a factor of two or more, experts said. Though this has been observed for years from population studies, scientists had not known what lay behind it. The new research, made possible by recent advances in DNA-sequencing technology, also should help correct an overemphasis on the riskiness of women giving birth at older ages, some researchers said.
December 10, 2012 |
Human DNA contains myriad individual differences that influence a host of traits, be they eye color or the ability to digest milk. Now a study shows that most of those tiny genetic variations are rare - and they arose in the very recent history of our species. Joshua Akey, a geneticist at the University of Washington in Seattle, led a consortium of scientists who examined the DNA of 4,298 European Americans and 2,217 African Americans. Limiting their analysis to the parts of the genome that contain instructions for making proteins, the study authors found more than 1 million sites where the building blocks of DNA - the nucleotides known by the letters A, C, G and T - varied in at least one of the subjects.
June 8, 2011 |
Autism spectrum disorders can be caused by as many as 300 or so rare genetic mutations, scientists reported Wednesday. The research strongly implicates genetics, including spontaneous gene mutations, in the development of the disorder. But why do four times as many males as females develop autism spectrum disorder? In one of the three papers published in the journal Neuron , researchers suggest that girls are more resistant to gene mutations than boys. Girls seem to require a higher number of gene mutations to become afflicted with autism spectrum disorder.
April 10, 2014 |
It's a flu virus so deadly that scientists once halted research on the disease because governments feared it might be used by terrorists to stage a biological attack. Yet despite the fact that the H5N1 avian influenza has killed 60% of the 650 humans known to be infected since it was identified in Hong Kong 17 years ago, the “bird flu” virus has yet to evolve a means of spreading easily among people. Now Dutch researchers have found that the virus needs only five favorable gene mutations to become transmissible through coughing or sneezing, like regular flu viruses.