Abstract
Genetic exchange is crucial for adaptation to stressful environments. However, in Leishmania, exposure to specific stressful conditions in the sand fly gut is likely to induce genetic exchange.
Access to the sand fly genome is now urgently required to facilitace the search for factors that stimulate Leishmania sex. The epidemiological consequences of genetic exchange in Leishmania are potentially alarming.
Akopyants et al. demonstrate two distinct virulence traits among hybrid Leishmania clones but do not dokument the effect of genetic exchange on development of Leishmania in the vector. There is, however, proof that sex enhances Leishmania fitness and transmission in the sand fly.
Leishmania infantum and L. major are divergent species, transmitted by different vectors to different mammalian reservoirs. Nevertheless, L. infantum/L. major hybrids complete the life cycle in Phlebotomus papatasi, the specific vector of L. major that does not support L. infantum.