¿Funciona la ley de equilibrio de hardy-weinberg en autopoliploides igual que en diploides? / Does the hardy-weinberg law of equilibrium work in autopolyploids as it does in diploids?

La ley del equilibrio Hardy-Weinberg es la piedra angular de la genética de poblaciones y la genética cuantitativa; sin embargo, para su cálculo en autopoliploides hay que tener en cuenta que las frecuencias alélicas y gaméticas son diferentes, caso contrario que los diploides donde son iguales. Esto ocasiona que el cálculo de esta fórmula deba hacerse con las frecuencias alélicas o las gaméticas basadas en las alélicas, de otra forma se puede romper el equilibrio de la población y el sesgo que esto conlleva en cálculos de otras pruebas como los estadísticos F de Wright, la GST de Nei o modelos bayesianos que se basan en los desequilibrios que presentan las poblaciones. Por eso este ensayo desarrolla los modelos de un locus con dos alelos en genotipos autotetraploides y autooctoploides para poder realizar una generalización de la ley del equilibrio en poblaciones autopoliploides.

The law of equilibrium Hardy-Weinberg is the cornerstone of the population genetics and of the quantitative genetics; however, for its calculation in autopolyploids it is necessary take in account that the allelic and gametic frequencies are different, contrary to the diploids where they are the same. This causes that the calculations must be done with the allelic frequencies or gametic based on allelic frequencies. Otherwise the equilibrium is broken in the population and the bias that this entails in the calculation of other genetical test like Wright's F statistics, the Nei's GST or Bayesian models that are based on the disequilibrium that populations show. That is why in this work they developed models of one locus with two alleles in autotetraploid and autooctoploid genotypes to make a generalization of the law of equilibrium in autopolyploid populations.

Experimental nodel of C6 brain tumors in athymic rats / Modelo experimental de tumor cerebral C6 em ratos atímicos

Malignant brain tumor experimental models tend to employ cells that are immunologically compatible with the receptor animal. In this study, we have proposed an experimental model of encephalic tumor development by injecting C6 cells into athymic Rowett rats, aiming at reaching a model which more closely resembles to the human glioma tumor. In our model, we observed micro-infiltration of tumor cell clusters in the vicinity of the main tumor mass, and of more distal isolated tumor cells immersed in normal encephalic parenchyma. This degree of infiltration is superior to that usually observed in other C6 models.

Modelos experimentais de tumores cerebrais malignos geralmente utilizam células imunologicamente compatíveis com o animal receptor. Neste estudo apresentamos um modelo experimental baseado na inoculação de células C6 em ratos atímicos Rowett, visando obter um tumor que se assemelhe mais àqueles observados nos seres humanos. Neste modelo observamos microinfiltração de ilhotas de células na periferia da massa tumoral principal e nas áreas mais distantes, células tumorais isoladas no tecido cerebral normal. Este grau de infiltração é superior àquele observado em outros modelos utilizando as células C6.