Posts Tagged ‘study’
Science: The human immunodeficiency virus (HIV-1) responsible for most of the AIDS cases in the world infected people approximately 100 years ago, more than 20 years earlier than previously believed, according to findings presented here this week at the Evolution 2008 meeting. Its lesser known cousin, HIV-2, jumped into humans decades later, from a monkey species that carried the virus for just a couple of hundred years, not the millions of years researchers had assumed, according to other research presented at the meeting.
Researchers are trying to pin down the origins of both HIVs to understand how often new human viruses emerge. Both arose from simian immunodeficiency viruses (SIVs) of other primates.
New Scientist: Brain scans have provided the most compelling evidence yet that being gay or straight is a biologically fixed trait.
The scans reveal that in gay people, key structures of the brain governing emotion, mood, anxiety and aggressiveness resemble those in straight people of the opposite sex.
The differences are likely to have been forged in the womb or in early infancy, says Ivanka Savic, who conducted the study at the Karolinska Institute in Stockholm, Sweden.
“This is the most robust measure so far of cerebral differences between homosexual and heterosexual subjects,” she says.
Previous studies have also shown differences in brain architecture and activity between gay and straight people, but most relied on people’s responses to sexuality driven cues that could have been learned, such as rating the attractiveness of male or female faces.