Tiny postcranial elements that apparently pertain to eosimiid anthropoids demonstrate that some Eocene primates were smaller than the smallest living mouse lemurs. The evolutionary dichotomy between anthropoids and tarsiiforms almost certainly occurred at or below the modern limits of body mass in the order Primates. A previously unsuspected interval of primate dispersal between Asia and North America is revealed by the recent discovery of a new fossil primate near the Sino-Vietnamese border. On the contrary, it is becoming clear that centromeric and pericentromeric regions are highly plastic. We have recently performed a systematic FISH studies showing that the vast majority of the human alphoid centromeric probes do not recognize their corresponding homologous chromosomes in great apes, indicating a very rapid evolution of these sequences.
Pericentromeric regions are also highly plastic.
A primate FISH analysis of probes from the pericentromeric regions of chromosome 10 have indicated that sequences across this region appear to have undergone unprecedented levels of duplication, transposition, inversion and either deletion or sequence divergence in all primate species analysed. Extrapolating the data to the whole genome suggests that a minimum of 50Mb of DNA in centromere proximal regions is subject to an elevated level of mechanistically diverse sequence rearrangements. The position of the centromere seems to have undergone, in some species, an evolutionary history independent from the surrounding markers. We recently found a better example of this paradox by comparing the conservation of chromosome X in two lemur species, the Black lemur and the Ring-tailed lemur. The marker order along these chromosomes, however, was found to be perfectly colinear with humans.