TAILIEUCHUNG - Báo cáo sinh học: "Of primordial genomes and cooperative kittens"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Of primordial genomes and cooperative kittens. | Journal of Biology BioMed Central Editorial Of primordial genomes and cooperative kittens Miranda Robertson Since every cell is derived from another cell and the genetic code is more or less universal - so that life cannot within the bounds of reasonable probability have evolved more than once - every living being must ultimately derive from an ancestral cell containing a primordial genome. The recognition of the very large part played by horizontal gene transfer in the evolution of bacterial genomes has however lately and notoriously undermined any hope we may have cherished of tracing the branches of our genomic ancestry back to their prokaryotic roots. In this issue of Journal of Biology Eugene Koonin and colleagues 1 describe an analysis of phylogenetic trees for 6 901 bacterial genes on the basis of which they conclude that ancestral gene-swapping notwithstanding a vertical signal sic can in fact be discerned at the deepest levels in the phylogenetic tree though it may never be possible to trace the branches. The extraction of tree structures from the web of gene transfers requires that transferred genes be subtracted by some means from the database of genes used to construct the trees. In the minireview accompanying the paper Kristen Swithers Peter Gogarten and Gregory Fournier 2 explain the philosophies and hazards of the strategies for such subtraction which include the danger of false vertical signals reflecting preferential gene transfer between bacterial species from quite separate branches of the phylogenetic tree and that happen to share a habitat 3 and the distinct approach whereby Puigbò et al. 1 sought to circumvent the problems of finding the true tree in the thicket. Whether because of horizontal gene transfer or the compression of branching events early in the evolution of prokaryotes the lines of vertical descent derived by Puigbò et al. from their analysis defy resolution at least for now and perhaps for ever. There is a character in the comic

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