Resumen

TURRENT FERNANDEZ, Antonio et al. Differences between classical plant breeding of maize and breeding through genetic engineering. Rev. Mex. Cienc. Agríc [online]. 2011, vol.2, n.6, pp.955-969. ISSN 2007-0934.

This essay discusses two statements: a) there are no fundamental differences between classical genetic improvement (CGI) or breeding and genetic engineering improvement (GEI); the latter is an extension of the first but is more accurate so, it gives greater safety to the consumer; and b) transformation by genetic engineering is equivalent to a natural mutation. CGI and the GEI pursue objectives that can be complementary; but its foundations, methods and biological implications are different: the CGI works within the limits of sexual compatibility, using the species genetic diversity as a favorable source of DNA, which gives the precision and recombination mechanisms of sexual reproduction. The CGI uses foreign DNA integrated into a transgenic chimera, which is inserted imprecisely known in the chromosomal space of the transforming and generates a different locus in each independent transgenic event. Such dispersion can lead to an accumulation of transgenic chimeras in their progeny, and possible deleterious effects. By excluding the quantitative phenotypic characteristics as yield, GEI depends on the progress made by the CGI to develop superior phenotypes. It's also concurred with the statement that, the transgenic insertion is a mutation with different implications for maize genome. The expression of each allele is regulated by the genome and epigenome to be activated or deactivated according to a development plan for growth of the genotype. In contrast, the transgene mutant is expressed somatically (in all plant cells, without pause).

Palabras llave : imprecision of transgenic locus; natural mutation; qualitative and quantitative traits; transformation.