A study by Yale researchers offers a new view of what causes the greatest genetic variability among individuals — suggesting that it is due less to single point mutations than to the presence of structural changes that cause extended segments of the human genome to be missing, rearranged, or present in extra copies.

Giardia lamblia, one of the most common human parasites in the United States, causes more than 20,000 intestinal infections a year, often through contact with contaminated drinking or swimming water. In the September 28 issue of Science, an international team led by researchers at the MBL (Marine Biological Laboratory) describe the complete genome (genetic sequence) of Giardia, which could lead to the development of new drugs to combat this persistent infection, called giardiasis.

Acid rain was one of the world’s worst pollution problems of the 1970s and 1980s, affecting large areas of upland Britain, as well as Europe and North America.

Determining the genetic profile of a particular lung tumor can help clinicians make the crucial decision about which chemotherapy treatment to try first.

Kaposi’s sarcoma herpesvirus (KSHV) is a human tumor virus and an etiological agent for Kaposi’s sarcoma (KS). KSHV infection is endemic in sub-Saharan Africa where KS is nowadays the most common malignancy, due to widespread infection with KSHV and human immunodeficiency virus (HIV). Importantly, KS also occurs in HIV-negative individuals. Researchers at the University of Helsinki, Finland, have discovered that activation of the DNA damage response in the early stages of KS development functions as an anti-cancer barrier also in virus induced malignancies.

H5N1 influenza, also known as avian influenza, is considered a major global threat to human health, with high fatality rates. While little had been known about the specific effects of H5N1 on organs and cells targeted by the virus, researchers at Beijing University, Columbia University Mailman School of Public Health, and SUNY Downstate report in the September 29, 2007 issue of the Lancet detailed studies of human H5N1 victims that shed light on the anatomic distribution of the virus and its pathogenesis. Using a combination of molecular and protein labeling techniques, the authors found that H5N1 is present in the gastrointestinal tract and immune and central nervous systems, as well as the respiratory tract. In one patient, virus was transmitted across the placenta to the fetus.

Researchers at the University of Illinois have used an innovative approach to reveal the molecular basis of altruistic behavior in wasps. The research team focused on the expression of behavior-related genes in Polistes metricus paper wasps, a species for which little genetic data was available when the study was begun. Their findings appear today online in Science Express.

Drawing of a woolly mammoth. Stephan C. Schuster and Webb Miller of Penn State University, working with Thomas Gilbert from Copenhagen and a large international consortium, discovered that hair shafts provide an ideal source of ancient DNA -- a better source than bones and muscle for studying the genome sequences of extinct animals. Their research achievement, described in a paper to be published in the journal Science on 28 September 2007, includes the sequencing of entire mitochondrial genomes from 10 individual woolly mammoths.