The FBI is working to quell skepticism surrounding its asserton that Bruce Ivins was behind the 2001 anthrax attacks. During two press briefings, agency reps laid out how they built their case with a mix of science and detective work. First, CDC analysis of the anthrax powder showed that it was not a uniform population, and then Paul Keim's group sequenced the variants' DNA. The FBI then searched anthrax repositories for four of those mutations and found eight samples -- all but one of which was in Ivins' lab. By checking lab notebooks and shipment records, they narrowed their scope to Ivins. Science also points out six questions that the FBI has not answered, including what those four mutations are.
Trichoplax adhaerens, also known as sticky hairy plate, has a surprisingly complex genome. It has 98 million DNA base pairs and genes needed for even more complex body parts to develop. Berkeley's Daniel Rokhsar also says Trichoplax adhaerens branched off after sponges but before cnidaria. "[It] highlights a disconnect between molecular and morphological complexity," says the University of Hawaii's Mark Martindale.
UCLA researchers report that epigenetic reprogramming via adenovirus proteins can result in cellular transformation. The scientists, led by Siavash Kurdistani, used ChIP and microarrays to examine the genome-wide binding of the adenovirus small e1a oncoprotein in fibroblasts at different time points. They saw that e1a displaces retinoblastoma proteins and p300/CBP histone acetyltransferases from promoters, stimulating cell cycling. Later, E1a binds to development and differentiation gene promoters to inhibit transcription. " By binding to the promoters of a large number of genes in a precise, time-dependent manner, e1a orchestrates redistribution of specific transcriptional co-regulators with associated epigenetic activities to promote S-phase entry and active repression of differentiation," write the authors.