Transformation of Monomorphic and Pleomorphic Trypanosoma brucei

African trypanosomes, such as Trypanosoma brucei , are protozoan parasites of mammals that were first described over 100 hundred years ago. They have long been the subjects of biological investigation, which has yielded insights into a number of fundamental, as well as novel, cellular processes in all organisms. In the last decade or so, genetic manipulation of trypanosomes has become possible through DNA transformation, allowing yet more detailed analysis of the biology of the parasite. One facet of this is that DNA transformation has itself been used as an assay for recombination and will undoubtedly lead to further genetic approaches to examine this process. Here we describe protocols for DNA transformation of Trypanosoma brucei , including two different life cycle stages and two different strain types that are distinguished by morphological and developmental criteria. We consider the application of transformation to recombination, as well as the uses of transforming the different life cycle stages and strain types.