Figure 3

Karyotype arrays of a normal female rat and of the rat mammary carcinoma RMT 47–3. Karyotype arrays are three-dimensional tables, which list the chromosome numbers of individual karyotypes on the x-axis, the copy numbers of each chromosome on the y-axis, and the number of karyotypes arrayed on the z-axis. In such arrays the karyotypes with identical, clonal chromosome copy numbers form parallel lines (see text). (A) An array of 20 karyotypes of a normal, diploid female rat. (B) An array of 20 karyotypes of the rat mammary carcinoma RMT 47–3. The karyotype array and the attached table show that the numbers of RMT 47–3 chromosomes per cell are quasi-clonal, averaging 43 ± 2. The data also show that the copy numbers of RMT 47–3 chromosomes are 70-100% clonal. The minority of non-clonal chromosomes oscillated within narrow margins of ±1 of clonal values, as predicted by the speciation theory (Background and Figure 1).