An unusual karyotypic observation on cultured cells from an owl monkey (Aotus trivirgatus).

A cell line, established from a pathological lymph node of an owl monkey, Aotus trivirgatus s.sp. trivirgatus, was found to have two cell populations distinguished from one another by chromosome number. The normal karyotype was present in the population of cells with 54 chromosomes; the other cell population, with 55 chromosomes, possessed a normal karyotype but with one additional abnormal chromosome. The significance of this extra chromosome is discussed.