|
|
|
|
|
| VALENZUELA,CARLOS Y; PÉREZ-ALZOLA,PATRICIA; SANTOS,MANUEL J. |
| The maximal value of 50 % of genetic recombination (RF = recombination fraction) between two linked gene loci has been explained by two models: (i) the restriction of crossovers to only two of the four chromatids of a tetrad (tetrad model); (ii) the limit of the occurrence of an odd number of crossovers between two loci, when the expected number of crossovers tends to infinite (odd-even model). This article shows that (i) is wrong. If tetrads were responsible for the maximal 50 % RF, sister chromatid exchanges (SCE) should display a maximal 100 % RF. In mammalian CHO cells we found that SCE yield a maximal 50 % recombination. Also, we demonstrated that the maximal 50 % RF for tetrads occurs because the sum of odd order coefficients in the binomial... |
| Tipo: Journal article |
Palavras-chave: 50 % recombination; Tetrads; Odd-even crossovers; SCE. |
| Ano: 2001 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2001000000015 |
| |
|
|
| VALENZUELA,CARLOS Y. |
| The synthetic theory of evolution proposes that biotic variations generated by mutation are mostly fixed, lost or maintained polymorphic by natural selection, with a marginal effect due to genetic drift. Based on the theory of autopoiesis some authors have proposed that selection is unable to explain most evolutionary changes, and natural or phenotype drift and epigenesis are the mechanisms that explain most of evolution. This view misunderstands basic evolutionary notions. Selection is a natural process that occurs with or without evolution; it does not explain evolution, it is a factor of the evolutionary process. The concept of autopoiesis implies an invariant condition of living beings, thus, it cannot explain and even less produce evolution conceived... |
| Tipo: Journal article |
Palavras-chave: Autopoiesis; Evolution; Natural drift; Neutral evolution; Selection; Synthetic theory. |
| Ano: 2007 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2007000100009 |
| |
|
|
| VALENZUELA,CARLOS Y. |
| Until now, there are three evolutionary models: I) The Synthetic Theory of Evolution (STE) also named as the Neo-Darwinian model; II) The Neutral Theory of Evolution (NTE) with its daughter the Nearly-Neutral Theory of Evolution (NNTE); III) The Theory of Evolution by means of Natural Drift (NDTE) (Valenzuela 2007, 2009). All these theories accept that variation of genomes of living beings emerges by mutation. They disagree in relation of the causes of the acquisition and maintenance of the living being organization. STE proposes that the main factor for the acquisition and maintenance of fixated organization is selection and a marginal role of genetic drift. NTE proposed that the acquisition and maintenance of fixated organization is drift with a marginal... |
| Tipo: Journal article |
Palavras-chave: Synthetic Theory of Evolution; Neutral Theory of Evolution; Natural Drift. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-078X2010000400004 |
| |
|
|
|
