A new gene chip from Santa Clara, CA based Affymetrix. (Courtesy of Affymetrix).

A new microarray that can simultaneously detect 500,000 or more specific genetic variations, covering almost every gene in the genome, will provide better insights into the complex genetic bases of many illnesses. Using the chip from Santa Clara, CA-based Affymetrix (a similar one is made by San Diego-based Illumina), researchers worldwide are seeking genetic causes of diseases such as autism, diabetes, and ­Alzheimer's. Below is a sampling of these efforts. Emily Singer

Select from the choices above to read the entire article.