Nature this week says that genome-wide association studies have reached a "fever pitch." The Wellcome Trust Case Control Consortium of 50 British research teams reports a study of more than 17,000 people. For each of the seven major diseases under scrutiny, they surveyed the genomes of about 2,000 people. Comparing these cases to controls, the consortium identified 24 risk factors: one for bipolar disorder, one for coronary artery disease, nine for Crohn's disease, three for rheumatoid arthritis, seven for type 1 diabetes, and three for type 2 diabetes (no risk factor was determined for hypertension). The related News and Views article points out that researchers still need to determine how environmental factors affects which people actually come down with the disease.
On a related note, a feature discusses establishing guidelines for genome-wide association studies. Replication, says the NCI-NHGRI Working Group on Replication in Association Studies, is needed to determine if an association is credible, but what constitutes appropriate replication isn't established. In addition to publishing their results, they suggest researchers should provide detailed experimental design information, as well as descriptions of their genotyping and statistical methods.
Moving away from association studies, University of Tokyo researchers report that the draft medaka (that's a bony fish) genome has 700 megabases — half the size of the zebrafish. By comparing the medaka to humans, pufferfish, and zebrafish, the researchers say that eight interchromosomal rearrangements occurred within 50 million years and after that, for more than 300 million years, the medaka kept the same karyotype.
As the New York Times points out, researchers have been building on Shinya Yamanaka's technique of reprogramming a skin cell to its embryonic state. In the advance online publication section of Nature, there is an article by Yamanaka and one led by Rudolf Jaenisch that improve upon and replicate the method of transferring four transcription factors into skin cells to make them pluripotent (there is a related article in Cell Stem Cell). The associated News and Views says, "The race is now on to apply the surprisingly straightforward procedure to human cells."