Plasticity of the histone H2A genes in a Brazilian and six Colombian strains of Trypanosoma cruzi

The analysis of three recombinant clones containing the histone H2A locus i solated from a genomic library of Trypanosoma cruzi DNA shows that the H2A gene loci are formed by 1.2 and 0.76 kb long intercalated units organized i n a head-to-tail tandem array. The difference in length between the two gen e units is due to the presence of a short interspersed nucleotide element ( SINE)-like DNA sequence inserted at the 3' end of some of these units. Sout hern, northern and chromosomal blot analysis of a Brazilian Y strain and si x Colombian strains demonstrated the existence of polymorphisms regarding t he relative copy number of the H2A gene units, the relative abundance of th e H2A transcripts and their chromosomal location. These results show the ex istence of a dynamic organization in the H2A loci among T, cruzi strains in which a SINE-like sequence may be involved and support the fact that T. cr uzi has a high degree of plasticity in its genome. (C) 2000 Elsevier Scienc e B.V. All rights reserved.