"The host-parasite relationship" is a vast and diverse research field
which, despite huge human and financial input over many years, remains
largely shrouded in mystery. Clearly, the adaptation of parasites to their
different host species, and to the different environmental stresses that
they represent, depends on interactions with, and responses to, various
molecules of host and/or parasite origin. The schistosome genome project is
a primary strategy to reach the goal; this systematic research project has
successfully developed novel technologies for qualitative and quantitative
characterization of schistosome genes and genome organization by extensive
international collaboration between top quality laboratories. Schistosomes
are a family of parasitic blood flukes (Phylum Platyhelminthes), which have
seven pairs of autosomal chromosomes and one pair of sex chromosomes (ZZ
for a male worm and ZW for a female), of a haploid genome size of 2.7x10^8
base pairs (Simpson et al. 1982). Schistosomes are ideal model organisms
for the development of genome mapping strategies since they have a small
genome size comparable to that of well-characterized model organisms such
as Caenorhabditis elegans (100 Mb) and Drosophila (165 Mb), and contain
functional genes with a high level of homology to the host mammalian genes.
Here we summarize the current progress in the schistosome genome project,
the information of 3,047 transcribed genes (Expressed Sequence Tags; EST),
complete sets of cDNA and genomic DNA libraries (including YAC and cosmid
libraries) with a mapping technique to the well defined schistosome
chromosomes. The schistosome genome project will further identify and
characterize the key molecules that are responsible for host-parasite
adaptation, i.e., successful growth, development, maturation and
reproduction of the parasite within its host in the near future.
