Here’s a link to a newly published paper at PLoS Genetics, and although my knowledge of centromeres is scant, it seems clear that the authors are confident that their research can effectively demonstrate  the timing of past waves of primate evolution going back as far as 35 million years, including periods of heightened activity, as explained here in the abstract:

Alpha satellite domains that currently function as centromeres of human chromosomes are flanked by layers of older alpha satellite, thought to contain dead centromeres of primate progenitors, which lost their function and the ability to homogenize satellite repeats, upon appearance of a new centromere. Using cladistic analysis of alpha satellite monomers, we elucidated complete layer patterns on chromosomes 8, 17, and X and related them to each other and to primate alpha satellites. We show that discrete and chronologically ordered alpha satellite layers are partially symmetrical around an active centromere and their succession is partially shared in non-homologous chromosomes. The layer structure forms a visual representation of the human evolutionary lineage with layers corresponding to ancestors of living primates and to entirely fossil taxa.

Surprisingly, phylogenetic comparisons suggest that alpha satellite arrays went through periods of unusual hypermutability after they became “dead” centromeres. The layer structure supports a model of centromere evolution where new variants of a satellite repeat expanded periodically in the genome by rounds of inter-chromosomal transfer/amplification. Each wave of expansion covered all or many chromosomes and corresponded to a new primate taxon.

Complete elucidation of the alpha satellite phylogenetic record would give a unique opportunity to number and locate the positions of major extinct taxa in relation to human ancestors shared with extant primates. If applicable to other satellites in non-primate taxa, analysis of centromeric layers could become an invaluable tool for phylogenetic studies.

The research seems to promise much for the future, particularly for those attempting to shed light on our distant primate ancestors, whose fossils are vanishingly rare, making it much harder for us to trace the exact sequence of evolutionary events that led to our own sweet selves appearing on the scene – being able to track the chronology and timing of pulses and sequences of evolution is interesting enough in itself, but it might be a while before an understanding of what caused these evolutionary events in ancestral primates can be firmly established, and whether or not any kind of punctuated equilibrium can be said to exist.

Reference: Shepelev VA, Alexandrov AA, Yurov YB, Alexandrov IA (2009) The Evolutionary Origin of Man Can Be Traced in the Layers of Defunct Ancestral Alpha Satellites Flanking the Active Centromeres of Human Chromosomes. PLoS Genet 5(9): e1000641. doi:10.1371/journal.pgen.1000641

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