Monday, January 21, 2008

Bioscience News Roundup: 01-21-08

Here are some interesting bioscience tidbits from the past week:

Valter Longo and colleagues have two upcoming papers that demonstrate the genetic control of aging (One of the articles will be in the January 25 issue of the open-access PLoS Genetics.). A combination of "genetic tinkering" - the inactivation of the RAS2 and SCH9 genes - and low-calorie diet allowed yeast to live 10 weeks instead of the usual one week. Longo and colleagues are studying a population in Ecuador that carry similar mutations.
“People with two copies of the mutations have very small stature and other defects,” he said. “We are now identifying the relatives with only one copy of the mutation, who are apparently normal. We hope that they will show a reduced incidence of diseases and an extended life span.”

Longo cautioned that, as in the Ecuador case, longevity mutations tend to come with severe growth deficits and other health problems. Finding drugs to extend the human life span without side effects will not be easy, he said.
Selva, The Scientific Indian, reports on a recent article in the New York Times about brain-machine interfaces. So far only monkeys, but can humans be far behind?

Nina Munteanu has an interesting post on synthetic bacteria and the possible dangers in "extreme genetic engineering."

Ed Yong writes about how and why temperature controls the gender of Jacky dragons.

io9 has a report on an experiment by Dr. Richard Behringer and colleagues that transplanted the DNA sequences that regulate the expression of the Prx1 gene from the bat to the mouse. The result was abnormally long forelimbs that were more bat-like than mouse-like.
Dr. Behringer describes the significance of his finding as such: "Darwin suggested that "successive slight modifications" would ultimately result in the evolution of diverse limb morphologies, like a hand, wing, or fin. The genetic change we engineered in mice may be one of those "slight modifications" to evolve a mammalian wing."
The news that hit the main stream media big this week was the announcement by the FA that cloned meat is considered safe to eat. The main public concern isn't that the cloned meat would be toxic, but that it's just "icky". Last October, Wired reported on cloned meat and milk that's already available, at least on a limited basis.

UK researchers have been given the go-ahead to make human-cow hybrids. Human DNA will be injected into "empty" cow eggs, resulting in embryos that are "99.9 per cent human in genetic terms", according to the article. There is more technical information on the proposal in Nature Cell Biology:
The proposals under consideration involve replacing the nucleus of an animal egg with the nucleus from a human somatic cell (Fig. 1), and allowing such an entity to develop in vitro for approximately 5 days until it forms a blastocyst (a sphere of 100 or so cells). This comprises an outer trophectoderm layer, destined to be part of the placenta, and the inner cell mass (ICM), which, if allowed to continue in the correct three-dimensional organisation, can give rise to the foetus and the remaining extraembryonic tissues. However, at this 5 day stage, the ICM cells would be used to establish hESC lines in vitro4. As there is no intention to implant any of these embryos to allow further development in the womb, which is already illegal in most countries (including the UK) whether using human or animal eggs as recipients, there is nothing in current legislation to prevent the experiments being conducted. The use of human oocytes to carry out similar procedures has already been licensed by the HFEA5, but the shortage of donated human oocytes6 has prompted the search for an alternative, hence the idea of using animal eggs.
It definitely won't result in critters that make LiveScience's Freakiest Lab Animal list.

Finally, the biotech company Stemagen has reported creating cloned human embryos using somatic cell nuclear transfer - the fusion of an adult skin cell with an egg. They didn't actuallly take the next step and demonstrate that the resulting embryos could be used as a source of stem cells. The reaction from the scientific community has ranged from skeptical to "what's the big deal?"

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