Chromosome number (2n)

Value 48 Unitless
Organism Chimpanzee Pan troglodytes
Reference Young WJ, Merz T, Ferguson-Smith MA, Johnston AW. Chromosome number of the chimpanzee, Pan troglodytes. Science. 1960 Jun 3 131:1672-3.PubMed ID13846659
Method Researchers have been able to ascertain the chromosome numbers of nine individuals of Pan troglodytes (seven males and two females), which were sacrificed because of infection with tuberculosis (3). Anesthesia was induced with ether and maintained for 3 to 5 hours with Nembutal. This period afforded sufficient time for the action of the mitotic poisons used: either colchicine, 0.25 mg/ kg injected intraperitoneally, or Colcemid (4), 6 mg per animal injected intravenously. Bone marrow was obtained from the proximal third of the humerus (in one case from the radius) it was suspended in 1.12 percent sodium citrate at 37°C for 20 to 30 minutes, centrifuged, and either fixed in cold alcohol-acetic acid and prepared by the Feulgen squash method (5) or fixed in 50 percent acetic acid and stained with lactic-acetic orcein and then squashed (6). Counts of suitable metaphase plates were made directly from the preparations.
Comments The chromosome numbers of nine chimpanzees have been determined by the bone marrow technique. The diploid number in this species is 48, with a probable XX-XY sex chromosome constitution. Notice that this is the 2n value, i.e. counting the sister chromosomes as two separate chromosomes. See BNID 100371
Entered by Ron Milo - Admin
ID 100323