In humans, faces are an important source of social information. One property of faces that is rapidly noticed is attractiveness. Research has highlighted symmetry and sexual dimorphism (how masculine/feminine a face is) as important variables that determine a face’s attractiveness.
But why are these traits attractive?
One idea is that both traits are adverts of genetic quality or some other aspect of quality such as fertility. An alternative view is that preferences for these traits arise through visual experience and therefore not linked to any underlying biological factors. Faces certainly have the potential to be advertisements of mate ‘quality’ and one way to examine this idea is to look at interrelationships between proposed adverts of quality.
Think it's tough for humans to find the right mate? Malagasy mouse lemurs are so similar that picking a mate of the right species, especially at night time in a tropical forest, was thought to be more luck than science, but new research has shown that our desperately cute distant cousins use vocalizations to pick up a partner of the right species.
Until recently, grey, golden brown, and Goodman’s mouse lemurs were all thought to be the same species. But genetic testing revealed that they are, in fact, three distinct, species so similar that they cannot be told apart by their appearance—so called cryptic species.
“A fundamental problem for cryptic species that live in the same area and habitat is the coordination of reproduction and discrimination between potential mates of the same species and remarkably similar individuals of other species” say Pia Braune and colleagues from the Institute of Zoology, University of Veterinary Medicine, Hannover University.
A common weedkiller in the U.S., atrazine, already suspected of causing sexual abnormalities in frogs and fish, has now been found to alter hormonal signaling in human cells, scientists from the University of California San Francisco (UCSF) report.
Atrazine is the second most widely used weedkiller in the U.S., applied to corn and sorghum fields throughout the Midwest and also spread on suburban lawns and gardens. It was banned in Europe after studies linked the chemical to endocrine disruptions in fish and amphibians.
In studies with human placental cells in culture, the UCSF scientists found that atrazine increased the activity of a gene associated with abnormal human birth weight when over-expressed in the placenta. Atrazine also targeted a second gene that has been found to be amplified in the uterus of women with unexplained infertility.
Health care in the United States is expensive, but its funding is crucial because it also is a major contributor to the economy and can better lives, according to an essay appearing in the June 2008 issue of the Journal of the American Society Nephrology (JASN).
Because of the cost of health care, this is not time to shrink the budget at the National Institutes of Health, which funds medical research that leads to potentially curative therapy, according to Dr. Eric Neilson, Editor-in-Chief of the Journal of the American Society Nephrology and Chair of the Department of Medicine at the Vanderbilt University School of Medicine in Nashville, TN.
As the US population increases, health care costs are sure to rise. To help stem rising health care costs, government officials are taking money away from Medicare and Medicaid programs, and budget planners are reducing the funds used to support medical science. But experts question this strategy, noting that health care employs a large segment of the national workforce (and is, therefore, a fundamental feature of the economy) and medical research is a critical enterprise that over the long run will provide more affordable health care—so called “high technology,” as Lewis Thomas once phrased it.
Genetic variation in the DNA of mitochondria – the 'power plants' of cells – contributes to a person’s risk of developing age-related macular degeneration (AMD), say investigators in the first study to examine the mitochondrial genome for changes associated with AMD, the leading cause of blindness in Caucasians over age 50.
“Most people don’t realize that we have two genomes,” said lead author Jeff Canter, M.D., M.P.H., an investigator in the Center for Human Genetics Research. “We have the nuclear genome – the “human genome” – that makes the cover of all the magazines, and then we also have this tiny genome in mitochondria in every cell.”
Canter teamed with Jonathan Haines, Ph.D., and Paul Sternberg, M.D., experts in AMD genetics and treatment, to examine whether a particular variation in the mitochondrial genome is associated with the disease. The genetic change occurs in about 10 percent of Caucasians, referred to as mitochondrial haplogroup T.
A new study by UC Davis researchers provides evidence that methods using human bone marrow-derived stem cells to deliver gene therapy to cure diseases of the blood, bone marrow and certain types of cancer do not cause the development of tumors or leukemia. The study was published online in the May 6, 2008 issue of Molecular Therapy.
"The results of our decade-long study of adult human stem cell transplantation shows that there is little risk of adverse events caused by gene transfer, and that adult human stem cells do not pose a cancer risk when implanted into different organs," said Jan Nolta, senior author of the study and director of the UC Davis Stem Cell Program.
Nolta and her colleagues tested the safety of gene transfer into bone marrow stem cells from human donors in more than 600 mice. None of the transplanted mice developed leukemia or solid tumors caused by the gene therapy treatment, during the evaluation period of up to 18 months.