Discussion

Schistosomes are custom designed for genetic analysis: we can conduct crosses in the laboratory to generate 1000s of progeny, clonal amplification within the snail host allows for accurate measurement of parasite phenotypes, and a developing molecular tool kit is available for functional dissection of candidate genes. Schistosome parasites show heritable genetic variation in compatibility with their snail hosts, in the numbers of transmission stages produced, in the time of day that they are produced. My laboratory is exploiting an old approach &hypen; linkage analysis of genetic crosses is now almost 100 years old &hypen; in combination with exome sequencing of parents and progeny, to understand the genetic determinants and evolution of these key transmission-related traits.