Transferência lateral de genes na evolução: fatos e desafios

Horizontal gene transfer in evolution: facts and challenges

Luis Boto*

Author Affiliations
Departamento Biodiversidad y Biología Evolutiva, Museo Nacional Ciencias Naturales, CSIC, C/José Gutierrez Abascal 2, 28006 Madrid, Spain
*mcnb119@mncn.csic.es

Asbtract

The contribution of horizontal gene transfer to evolution has been controversial since it was suggested to be a force driving evolution in the microbial world. In this paper, I review the current standpoint on horizontal gene transfer in evolutionary thinking and discuss how important horizontal gene transfer is in evolution in the broad sense, and particularly in prokaryotic evolution. I review recent literature, asking, first, which processes are involved in the evolutionary success of transferred genes and, secondly, about the extent of horizontal gene transfer towards different evolutionary times. Moreover, I discuss the feasibility of reconstructing ancient phylogenetic relationships in the face of horizontal gene transfer. Finally, I discuss how horizontal gene transfer fits in the current neo-Darwinian evolutionary paradigm and conclude there is a need for a new evolutionary paradigm that includes horizontal gene transfer as well as other mechanisms in the explanation of evolution.

evolution horizontal gene transfer evolutionary mechanisms

Recently, several calls have been put forward for a new evolutionary synthesis (Dean & Thornton 2007; Pigliucci 2007; Carroll 2008; Koonin 2009) that encompasses mechanisms other than mutation, natural selection and drift to explain evolutionary changes, such as developmental constraints and epigenetic modifications among others.

Today it seems evident, from the studies discussed below, that horizontal (or lateral) gene transfer, the direct visualization of which has been achieved recently (Babić et al. 2008), is an important force driving the evolution of Bacteria and Archaea, as well as that of unicellular eukaryotes, and should therefore also be considered as part of the structure of any evolutionary synthesis.

Horizontal gene transfer, ‘the non-genealogical transmission of genetic material from one organism to another’ (Goldenfeld & Woese 2007), is a source of new genes and functions to the recipient of the transferred genetic material. In this sense, it is a mechanism that permits the acquisition of evolutionary novelties. But these acquisitions are primarily non-genealogical, questioning, in my opinion, the neo-Darwinian conception of a gradualist process driving the appearance of novel traits and functions.

In this review, I will discuss how horizontal gene transfer fits in with current evolutionary thinking, as well as the challenges that it proposes for the current evolutionary paradigm.

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NOTA DESTE BLOGGER:

Pela data do artigo, eu creio que já postei aqui alguma coisa a respeito. Se for assim, vale a pena destacar em itálicos alguns trechos do abstract e deixar a Galera dos meninos e meninas de Darwin perplexa: os próprios evolucionistas reconhecem que há uma crise epistêmica da Síntese Evolutiva Moderna, e há necessidade de uma nova teoria - a SÍNTESE EVOLUTIVA que não pode e nem deve ser selecionista.

Será que a Nomenklatura científica vai anunciar a nova teoria em 2010? Dia 12 de fevereiro de 2010 não pode ser, pois é o aniversário de Darwin, o homem de Down que teve a maior ideia que toda a humanidade já teve.