Yeast stimulation of bone marrow mitosis for cytogenetic investigations.

We report a simple, dependable method for stimulating bone marrow mitosis in small mammals. Subcutaneous injections of a suspension of active baker's yeast may elevate the mitotic index as much as six times or more. Additionally, the metaphases obtained are easily spread when air dried, and the chromosomes are readily banded. This method should prove useful to investigators who wish to use bone marrow as a source of chromosomes for cytotaxonomic studies or for studies of specific chromosome damage in vivo.