Redalyc.TOWARDS a NEW EVOLUTIONARY THEORY
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Interciencia ISSN: 0378-1844 [email protected] Asociación Interciencia Venezuela Pérez, Julio E.; Alfonsi, Carmen; Muñoz, Carlos TOWARDS A NEW EVOLUTIONARY THEORY Interciencia, vol. 35, núm. 11, noviembre, 2010, pp. 862-868 Asociación Interciencia Caracas, Venezuela Available in: http://www.redalyc.org/articulo.oa?id=33915598013 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative TOWARDS A NEW EVOLUTIONARY THEORY Julio E. Pérez, Carmen Alfonsi and Carlos Muñoz SUMMARY The need to elaborate a new evolutionary theory is discussed. mechanisms: natural selection, gene flow, genetic drift, fusion Several arguments are given to justify a new theory, mainly of genomes and gene fragments, epigenetic mechanisms such as based on present interpretation of different phenomena such methylation of DNA, tool kits, regulatory cis-elements, hybrid- as endosymbiosis, reticulate evolution, the modern synthesis of ization and polyploidy. As well as mutations, other sources of embryonic development and evolution (evo-devo), phenotypic genetic variation must also be included. plasticity, epigenesis, evolvability, and the several evolutionary HACIA UNA NUEVA TEORÍA DE LA EVOLUCIÓN Julio E. Pérez, Carmen Alfonsi y Carlos Muñoz RESUMEN Se analiza la necesidad de elaborar una nueva teoría de la varios mecanismos evolutivos: selección natural, flujo génico, evolución. Se señalan varios argumentos para justificar una deriva génica, fusión de genomas y fragmentos génicos, metila- nueva teoría, basados principalmente en la actual interpretación ción de ADN, “cajas de herramientas”, elementos reguladores de diferentes fenómenos tales como endosimbiosis, evolución re- cis, hibridación y poliploidía. Además, se hace necesario incluir ticulada, síntesis moderna del desarrollo y la evolución (evo-de- diversas fuentes de variación, no solamente mutaciones. vo), plasticidad fenotípica, epigénesis, y evolucionabilidad, y de RUMO A UMA NOVA TEORIA DA EVOLUÇÃO Julio E. Pérez, Carmen Alfonsi e Carlos Muñoz RESUMO Analisa-se a necessidad de elaborar uma nova teoria da evo- de vários mecanismos evolutivos: seleção natural, fluxo gênico, lução. São apontados vários argumentos para justificar uma deriva gênica, fusão de genomas e fragmentos gênicos, meti- nova teoria, baseados principalmente na atual interpretação de lação de ADN, “caixas de ferramentas”, elementos reguladores diferentes fenômenos tais como endossimbiose, evolução reticu- cis, hibridação e poliploidia. Além disso, é necessário incluir lada, síntese moderna do desenvolvimento e a evolução (evo- diversas fontes de variação, não somente mutações devo), plasticidade fenotípica, epigênese, e evolucionabilidade, e Introduction nothing more than an ex- tion through the accumula- generations through chromo- trapolation and magnification tion of these chromosome somal change– be described How can the synthetic the- of the events that take place changes. These are largely as a small genetic change? ory be defined? In the words within populations and spe- independent of changes in The synthetic theory has of one of its main proponents cies (microevolution). the genes affecting external shown great capacity to in- (Mayr, 1963) the synthetic According to Stebbins morphology; thus, morpho- corporate new ideas. For ex- theory maintains that all evo- (1950), another proponent of logically undifferentiated spe- ample, the paper by King lution is due to the accumu- the modern synthesis, the cies may exhibit substantial and Jukes (1969) on neutral- lation of small genetic chang- theory also includes poly- chromosomal differences. ism and genetic drift as a es guided by natural selec- ploidy, translocations, and But, how can polyploidy new evolutionary mechanisms tion, and that transpecific other chromosomal mutations –a case of rapid speciation was titled ‘Non-Darwinian evolution (macroevolution) is that allow reproductive isola- requiring only one or two evolution’, although it seems KEYWORDS / Endosymbiosis / Epigenetic Changes / Evo-Devo / Phenotypic Plasticity / Reticulate Evolution / Received: 11/06/2009. Modified: 09/29/2010. Accepted: 10/08/2010. Julio E. Pérez. M.A. in Zoology, Address: Instituto Oceanográ- Carmen Alfonsi. M.Sc. in Ma- Carlos Muñoz. M.Sc. in Ma- University of Kansas, USA. fico de Venezuela, Universidad rine Sciences, IOV-UDO, rine Sciences, IOV-UDO, Ph.D. in Biology, University of de Oriente, Núcleo Sucre, Venezuela. Dr. in Zoology, Venezuela. Professor, Univer- Southampton, UK. Professor, Cumaná, Venezuela. e-mail: Universidad Central de Ven- sidad Arturo Prat, Iquique, Instituto Oceanográfico de [email protected] ezuela. Professor, IOV-UDO, Chile. e-mail: c.munoz@ Venezuela (IOV), Universidad Venezuela. e-mail: calfonsi@ unap.cl de Oriente (UDO), Venezuela. sucre.udo.edu.ve 862 0378-1844/10/11/862-07 $ 3.00/0 NOV 2010, VOL. 35 Nº 11 to have remained firmly evolution ever varied. For confront and overcome cur- light of new advances in mo- within the fold of the syn- him, essentially, it is a theory rent critiques that it loses all lecular biology. In his own thetic theory. On the other of differential rates of evolu- meaning by including every- words: “It would seem justi- hand, Mayr denied that ran- tion; a modification of Dar- thing. However, Gould fied to assert that, so far, no dom genetic drift is an evo- win’s gradualist model, not a (2002) wrote: “Nothing revision of the Darwinian lutionary mechanism. In his saltationist theory. about microevolutionary ge- paradigm has been necessary book What Evolution Is, netic population, or any oth- as a consequence of the spec- Mayr (2001) wrote: “Molecu- Is another evolutionary er aspect of microevolution- tacular discoveries of molec- lar genetics has found that theory needed? ary theory, is wrong or inad- ular biology.” mutations frequently occur in equate at its level. The mod- Pigliucci (2007) indicated which the new allele produc- Modern synthesis current- ern synthesis is incomplete, that there are some major el- es no change in the fitness of ly reigns as the official sci- not incorrect.” ements missing from the the phenotype. Kimura (1983) entific explanation for evolu- Then Ayala (2005) asked: modern synthesis: embryolo- has called the occurrence of tion (teaching evolution in “Is Gould claiming an expan- gy or development biology; such mutations ‘neutral evo- high schools and colleges sion with some modification the role of ecology in the lution’, and other authors means teaching the synthetic of the Modern Synthesis or is evolution of phenotypic nov- have referred to it as non- theory), having great influ- he claiming something more elties or during major transi- Darwinian evolution. Both ence on both our interpreta- ambitious, namely the ad- tions in evolution; knowledge terms are misleading. Evolu- tion of biodiversity and our vance of a new theory, even related to genomics, pro- tion involves the fitness of understanding of the world. if within the Darwinian tra- teomics, and the other new individuals and populations, Nevertheless, present inter- dition? Gould’s statements, in “-omics” sciences; and sev- not of genes. When a geno- pretation of different phe- the structure and elsewhere, eral important biological phe- type, favored by selection, nomena such as endosymbio- are inconsistent, if not con- nomena, such as phenotypic carries along as hitchhikers a sis, reticulate evolution, the tradictory.” plasticity, the possibility of few newly arisen and strictly modern synthesis of embry- Gould (2002) indicated that evolutionary capacitance, and neutral alleles, it has no in- onic development and evolu- the study of microevolution epigenetic inheritance. Ac- fluence on evolution. This tion (evo-devo), phenotypic provides little, if any, infor- cording to Pigliucci (2007), may be called ‘evolutionary plasticity, evolvability and mation about macroevolution- non-random epigenetic noise’, but it is not evolu- the several evolutionary ary patterns. Macroevolution changes must be the most tion”. mechanisms: natural selec- is autonomous relative to mi- important factor in a new However, in the opinion of tion, gene flow, genetic drift, croevolution. Although Ayala theory of evolution. Epigen- Stebbins and Ayala (1981), fusion of genomes and gene (2005) supported this idea, etic variation, unlike genetic the “selectionist” and the fragments, methylation of he indicated that the study of variation, can be altered di- “neutralist” views of molecu- DNA, tool kits, regulatory microevolutionary phenomena rectly by the environment lar evolution are competing cis-elements, hybridization is important to macroevolu- and may be inherited by fu- hypotheses within the frame- and polyploidy, indicates the tion, because any correct ture generations. Epigenetic work of the synthetic theory necessity to develop a new theory of macroevolution changes offer an additional of evolution. evolutionary theory, a coher- must be compatible with pathway for evolution. Another example of the ent alternative to modern well-established microevolu- incorporation of new ideas synthesis. As well as muta- tionary principles and theo- Elements to be into the synthetic theory is tions, other sources of ge- ries. In these two senses – incorporated in a new that of punctuated equilibri- netic variation must also be identity at the level of events