Interspecific heterokaryons between oocytes and blastomeres of the mouse and the bank vole.

Interspecific hybrid cells were produced using Sendai-virus-mediated fusion of interphase blastomeres from 2-cell embryos with ovulated oocytes of the mouse and bank vole. Under the influence of the cytoplasm of oocytes (arrested in metaphase II) premature chromosome condensation occurs in the nuclei of blastomeres, thus implying that the cytoplasmic factor which induces chromosome condensation is not species specific, at least not between these two species.