Self-fertilisation in Trypanosoma brucei.

We have investigated whether Trypanosoma brucei can undergo self-fertilisation. A group of 27 metacyclic clones derived from the tsetse transmission of a mixture of two genetically marked stocks was analysed and 22 clones were observed to be of non-hybrid phenotype. A group of 10 clones from this non-hybrid subset were then analysed for one isoenzyme, one restriction fragment length polymorphism and three karyotype markers potentially informative for the detection of self-fertilisation. Five of the 10 clones were found to be recombinant for at least one marker and we interpret these recombination events as indicating the clones to be products of self-fertilisation. We have also analysed a limited number of metacyclic clones from stocks of T. brucei each singly transmitted through tsetse flies but, so far, no evidence of recombination has been detected. We conclude that T. brucei is able to self-fertilise but there may be a requirement for the presence of dissimilar stocks to initiate such an event.