Word: variants
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...Paris New HIV Strain Discovered Fighting AIDS just got tougher. Unlike the three previously known strains of HIV, which have been linked to chimpanzees, a new variant--discovered in a 62-year-old Cameroonian woman who tested positive in 2004--appears to have come from gorillas. Researchers say the new strain may be difficult to detect using conventional tests but expect current treatments to remain effective...
...helping the virus replicate once inside a human cell. But certain amino-acid changes in the neuraminidase can render Tamiflu ineffective. This usually happens over time following extensive prescribing of the drug, but it can also occur spontaneously. In the winter of 2007-'08, a seasonal H1N1 variant circulating in Europe did just that, catching scientists by surprise. "We really didn't see that coming," says Daniels, who was one of the first scientists to identify the change. "Suddenly, an increasing number of H1N1 isolates were Tamiflu-resistant, and the resistant strains have persisted such that over 95% of H1N1...
...study published on June 16 in the Journal of the American Medical Association (JAMA) now threatens to send researchers back to the drawing board. The meta-analysis of 14 prior studies concludes that the so-called depression gene - a variant of a serotonin-transporter gene called 5-HTTLPR - may not be associated with an elevated risk for depression, as many researchers had believed. "Knowing whether or not you have this gene is irrelevant," says the study's co-author Kathleen Merikangas, a genetic epidemiologist at the National Institute of Mental Health, who adds that future studies of genetic risk factors...
...Meta-analyses can be a steamroller," says Alexandre Todorov, a genetic epidemiologist at Washington University in St. Louis, Mo., whose 2007 peer-reviewed study was included in the JAMA piece. (While Todorov's study found an association between the gene and depression, it was based on a different variant - the long allele as opposed to the short one.) "If you have three studies and two find nothing and the third finds something significant, that does not mean that the third study is not real...
...Males, who have one X chromosome and one Y chromosome, possess only one copy of this gene, while females, who have two X chromosomes, carry two," Beaver says. "Thus, if a male has a variant for the MAO-A gene that is linked to violence, there isn't another copy to counteract it." (See the top 10 scientific discoveries...