Chromosomal polymorphism and somatic segregation in Saimiri sciureus.

Quinacrine (Q) and Giemsa (G) banding, and sister chromatid exchange (SCE) studies have been carried out in Saimiri sciureus. In one male and one female studied, the diploid number was 2n = 44 and the karyotype corresponded to that described for the geographical region of Georgetown, Guyana. In the second male three different cell lines were observed, one corresponding to the geographical region of Leticia (Colombia), another to the geographical location of Iquitos (Peru) and a third line with 46 chromosomes. In the three lines, pair A2 was heterozygous, with nucleolar organizers of different size, and pari B6 was also heterozygous, with different amounts of heterochromatin in the short arms. The presence of three different cell lines in this male may be due to a mechanism of somatic segregation. The chromosomal changes involved in the intraspecific polymorphism found in Saimiri have been reinterpreted.