Data for: Unequal distribution of genes and chromosomes refers to nuclear diversification in the binucleated Giardia intestinalis.

The described chromosomal deletion has always been observed at the monosomic chromosome in WBc6; however, the deletion was not detected in the parent line WB. The chromosomal segment was thus initially lost after biological cloning of WB, which gave rise to clone WBc6. We show that Giardia is capable of carrying out gene expression from only one nucleus.

The two nuclei display a certain level of diversity, making each of them irreplaceable. The doubled karyomastigonts of diplomonads likely have separate functions both in the mastigont/flagellar organization and in chromosomal and gene content. Our results offer the first methodical approach to differentiating the two, so far indistinguishable nuclei.