Multiple origins of llife (Introduction)
A horizontal gene transfer expert scientist suggests multiple origins of life are possible:-http://www.annualreviews.org/doi/pdf/10.1146/annurev-genet-110711-155529-"CONCLUSION Let's reexamine one of Charles Darwin's famous quotes, taken from the final line in The Origin of Species: “There is grandeur in this view of life, with its several powers, having been originally breathed into a few forms or into one.” This sentence is prescient in its acknowledgment that life might indeed have multiple origins. Haeckel was the first to unambiguously present the modern concept of the tree of life originating from a common ancestor. The tree as a pure representation of vertical evolution was reinforced by the introduction of Mendelian genetics, which understandably focused on sexual reproduction because it is the dominant form of gene flow among modern eukaryotes. The biological unities revealed by modern molecular biology were interpreted as further evidence of the existence of a common universal ancestor. But Darwin was wise to finesse this issue because horizontal gene flow is a recently discovered variable that needs to be considered."-It is a long and thorough article about HGT and ends with this suggestion that to explain the lack of a genetic tree of life might be explained by HGT and multiple origins.
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