A GROUP OF GIARDIA-LAMBLIA VARIANT-SPECIFIC SURFACE PROTEIN (VSP) GENES WITH NEARLY IDENTICAL 5'-REGIONS

The surfaces of Giardia lamblia trophozoites contain one of a set of v ariant-specific surface proteins. The genes encoding these proteins ar e highly conserved at the 3' terminus, but frequently demonstrate litt le similarity in the remainder of the coding region. This report descr ibes a family of vsp genes highly similar to a repeat-containing vsp g ene (vspC5) at the 5' coding and flanking regions, but which diverge a bruptly from vspC5 in the first repeat and do not themselves contain f ull copies of the repeat. This observation suggests the possibility th at recombination among different vsp genes may have played a role in d evelopment of the vsp gene repertoire.