Given the wide variety of different molecular biology methods available, it is probably just a matter of time before an approach to genotyping hits the market that is cheap enough for large scale genetic studies. Single base primer extension, for example, is sensitive enough to detect SNPs, but has not been compatible with large-scale, parallel analysis. However, researchers at the Whitehead Institute may have overcome that obstacle.

In last week's Proceedings of the National Academy of Sciences, researchers at the Whitehead (Cambridge, Mass.) and colleagues published a method for genotyping large numbers