Progressive proximal expansion of the primate X chromosome centromere

摘要: Previous studies of the pericentromeric region human X chromosome short arm (Xp) revealed an age gradient from ancient DNA that contains expressed genes to recent human-specific at functional centromere. We analyzed finished sequence this genomic investigate its evolutionary history. Phylogenetic analysis >1,500 alpha-satellite monomers presence five physical domains, each containing a distinct phylogenetic clade. The most distal domain long interspersed nucleotide element repeats were active >35 million years ago, whereas four proximal domains contain more recently repeats. An out-of-register, unequal recombination (i.e., crossover) detected edge chromosome-specific array (DXZ1) may reflect series punctuating events during evolution resulted in expansion first 18 kb has 97–99% pairwise identity among all 2-kb repeat units. To perform detailed comparisons, we sequenced junction between Xp and primate-specific alpha satellite chimpanzee, gorilla, orangutan, vervet, macaque, baboon. striking conservation found cases supports ancestral nature location. These demonstrate primate centromere appears have evolved through repeated occurring within central, centromeric DNA, with newly added sequences then conferring function.