The May issue of CSH Protocols is now live, and in it you’ll find featured articles on classic techniques for the analysis of chromosomes. With the leaps and bounds being made in epigenetics these days, knowing your way around chromatin becomes even more valuable. This month’s freely accessible articles give you methods for chromosome analysis in Drosophila and in Mouse.

Mapping Protein Distributions on Polytene Chromosomes by Immunostaining takes advantage of the formidable size and structure of the large polytene chromosomes found in Drosophila salivary glands. These easily dissected chromosomes allow mapping of chromosomal protein distributions at very high resolution. May’s issue also contains a protocol for the Dissection of Larval Salivary Glands and Polytene Chromosome Preparation.

The second featured method for May, Karyotyping Mouse Cells, is drawn from the widely used laboratory manual Manipulating the Mouse Embryo. A karyotype is a visual presentation of a cell’s chromosomes, and can be used as a test for quickly identifying chromosomal abnormalities.