Figure 1.

General description of primates

(A) Simplified phylogenetic tree of primates including rodents. Primates are separated roughly into three groups: New World monkeys, Old World monkeys, and Great apes. Of these, chimpanzees, rhesus and cynomolgus monkeys, and marmosets have been used for biomedical research, while the Great apes are no longer permissible in invasive experiments. mya, million years ago.

(B) Summary table of general information. Generally, primates have evolved to increase their body size and life span, and reduce their litter numbers. However, marmosets and most New World monkeys have small body size and relatively short generation periods. Marmosets also have an interesting feature: the generally produce dizygotic twins sharing a single placental system. y.o., years old; wk.o., weeks old.