The chromosomal Origin of Man

The Evolutionary Origin of Man Can Be Traced in the Layers of Defunct Ancestral Alpha Satellites Flanking the Active Centromeres of Human Chromosomes. The authors are Russian, so I think the somewhat grand and archaic first portion of the title can be explained as a mater of translation. Here's the author summary:

The primate centromere evolves by amplification of alpha satellite sequences in its inner core, which expands and moves the peripheral sequences sideways, forming layers of different age in the "pericentromeric" area. The expanding centromere model poses two main questions: (1) whether the succession of layers is symmetrical on both sides of the centromere, and (2) whether different chromosomes share the same layers. We have analyzed and dated the layers on both sides of human chromosomes 8, 17, and X and shown that they were largely symmetrical on one chromosome and largely shared and arranged similarly in non-homologous chromosomes. The layer pattern revealed that genome-wide waves of expansion of new satellite variants have occurred repeatedly in the human evolutionary lineage. The layers which are likely to be the relic centromeres of our common ancestors with primate taxa follow each other in chronological order. The two layers that do not match any living primate indicate the two completely extinct ancestral taxa aged 26-40 and 18-23 million years. These could be Propliopithecidae (Cathopitecus and Egyptopithecus) and Pliopithecidae (Proconsul), aged 33-35 and 17-27 million years, respectively. The possibility to reveal and date extinct ancestors makes the analysis of satellite layers a unique tool for the reconstruction of primate phylogeny.

This seems like a step forward in the synthesis between molecular evolution and fossil based paleoanthropology which began in the 1970s. And really, they're talking about the "human evolutionary lineage." Doesn't seem like they've found the "man gene," whatever that may be....

Citation: 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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this find has been around a few years. there's a lot of debate about what it might mean. the ideas are older than this find, popular laid out by william calvin in a book in the 1980s.

I teach anthropology and refer to this as the future field (within human genomics)of "genetic archaeology". I tell my students to stay tuned for the latest in the discovery and reconstruction of our past primate geneology and the genetic "turning points" in our prehistory from mining DNA and, in this case, the structure of chromosomes for information. It is fascinating to know that there arelayers of chromosomes just as there are strata in the earth that are chronologically arranged!

By Christina Miln… (not verified) on 10 Oct 2009 #permalink