PRESIDENTIAL ADDRESS SEX AND SCHISTOSOMES: AN INTERESTING BIOLOGICAL INTERPLAY WITH CONTROL IMPLICATIONS

Inside the snail the parasite undergoes asexual reproduction, resulting in an amplification of the genome, such that thousands of cercariae are produced. [...]a single miracidium will give rise to a clonal population of cercariae that are all of the same sex. The messenger RNA (mRNA) encoding p14 is present only in mature female worms and is not detectable in female schistosomes from single-sex infection, in male worms from single-sex or bisex infection, or in eggs. [...]expression (as determined by the detection of steady-state mRNA) of this gene is female specific. During normal bisexual infections, this mRNA is first detected 28 days postinfection (the time of worm pairing), increases to a high level at 35–37 days postinfection (coinciding with the start of egg production), and plateaus at 45 days postinfection, a time when most of the female parasites are fully developed and when egg production is constant (Fig. 1). [...]the temporal expression of the gene is dependent upon a male stimulus (pairing). Figure 1. Expression of p14 gene throughout development in the vertebrate host. [...]the high rate of gene expression in