An evaluation of HapMap sample size and tagging SNP performance in large-scale empirical and simulated data sets

A substantial investment has been made in the generation of large public resources designed to enable the identification of tag SNP sets, but data establishing the adequacy of the sample sizes used are limited. Using large-scale empirical and simulated data sets, we found that the sample sizes used in the HapMap project are sufficient to capture common variation, but that performance declines substantially for variants with minor allele frequencies of <5%.     

An integrated view of the chemistry and mineralogy of martian soils

The mineralogical and elemental compositions of the martian soil are indicators of chemical and physical weathering processes. Using data from the Mars Exploration Rovers, we show that bright dust deposits on opposite sides of the planet are part of a global unit and not dominated by the composition of local rocks. Dark soil deposits at both sites have similar basaltic mineralogies, and could reflect either a global component or the general similarity in the compositions of the rocks from which they were derived. Increased levels of bromine are consistent with mobilization of soluble salts by thin films of liquid water, but the presence of olivine in analysed soil samples indicates that the extent of aqueous alteration of soils has been limited. Nickel abundances are enhanced at the immediate surface and indicate that the upper few millimetres of soil could contain up to one per cent meteoritic material.     

Effect of sodium fluoride on the epinephrine response of liver and hepatoma adenyl cyclase

Zusammenfassung Die in vitro Stimulation der Adenyl-Cyclase durch Epinephrin zur Bildung der zyklischen AMP ist im Hepatomgewebe signifikant höher als in der normalen Rattenleber. Sodiumfluorid hemmt in beiden Fällen die Stimulation.     

Functional improvement of dystrophic muscle by myostatin blockade

Mice and cattle with mutations in the myostatin (GDF8) gene show a marked increase in body weight and muscle mass, indicating that this new member of the TGF-beta superfamily is a negative regulator of skeletal muscle growth. Inhibition of the myostatin gene product is predicted to increase muscle mass and improve the disease phenotype in a variety of primary and secondary myopathies. We tested the ability of inhibition of myostatin in vivo to ameliorate the dystrophic phenotype in the mdx mouse model of Duchenne muscular dystrophy (DMD). Blockade of endogenous myostatin by using intraperitoneal injections of blocking antibodies for three months resulted in an increase in body weight, muscle mass, muscle size and absolute muscle strength in mdx mouse muscle along with a significant decrease in muscle degeneration and concentrations of serum creatine kinase. The functional improvement of dystrophic muscle by myostatin blockade provides a novel, pharmacological strategy for treatment of diseases associated with muscle wasting such as DMD, and circumvents the major problems associated with conventional gene therapy in these disorders.     

Taphonomy and significance of Jefferson's ground sloth (Xenarthra: Megalonychidae) from Utah

While a variety of mammalian megafauna have been recovered from sediments associated with Lake Bonneville, Utah, sloths have been notably rare. Three species of ground sloth, Megalonyx jeffersonii, Paramylodon harlani, and Nothrotheriops shastensis , are known from the western United States during the Pleistocene. Yet all 3 are rare in the Great Basin, and the few existing records are from localities on the basin margin. The recent discovery of a partial skeleton of Megalonyx jeffersonii at Point-of-the-Mountain, Salt Lake County, Utah, fits this pattern and adds to our understanding of the distribution and ecology of this extinct species. Its occurrence in Lake Bonneville shoreline deposits permits a reasonable age determination of between 22 and 13 ka.