Ensaio Opcional (03/10/17)
One of the most remarkable characteristics of the genetic code is their capacity of redundancy, meaning that most amino acids can be encoded by more than one three-base pair codon. Nucleotide base substitution occurs at different rates and have different consequences; thus, changes in the third codon base are most frequent than substitutions in the first and second positions. Commonly, a change in the third position does not lead to changes in the encoded amino acid. On the other hand, changes in first and second positions are always critical -specially in the second-; since they can originate point mutations, by encoding a different amino acid or by the appearance of stop codons, that may result in the translation of non-functional proteins. Since codon degeneracy is a natural mechanism to protect the genetic information against mutations and it is present in all living systems, this variation in the frequency of substitution has allowed to recover the phylogenetic signal for the reconstruction of evolutionary relations of organisms.
Comentário por Pietro
De forma geral eu considero o ensaio muito bom. A escrita está direta; a maior parte das frases apresentadas são curtas e diretas. Também pude identificar a ideia sentença tópico no começo do ensaio. Eu sugiro que se divida a primeira e a última sentença do ensaio em duas para que a escrita fique mais direta. As demais sentenças do ensaio estão boas e de acordo com esse conceito de escrita.
Ensaio 1 (03/17/17)
Before cell division occurs, DNA must be duplicated in order that each one of the daughter cells holds a copy of genetic material. The mechanism by which DNA is duplicated is called replication, and it is a semi-conservative process. DNA replication is referred as semi-conservative, because of one DNA molecule are created two identical replicas; each one conserving an original strand and a new one, which is synthesized by adding nucleotides that complement the template strand. DNA replication is not bug free, and errors can lead to mutations that can trigger different genetic diseases. It is therefore, that cells have mechanisms to check and repair faults during and after replication. Different pathways for DNA repair are present in all extant lineages, and they are vital for maintain the accuracy of replication, and with that life prosperity.
Comentários por Stefany A. de Angelis:
Senti falta de uma frase introdutória. Algo como "No processo da Replicação genica[…]. Antes da divisão ocorrer[…]."
Nesta frase "DNA replication is not bug free[…]", eu escreveria: "This process is not bug free […]". Pois já está subentendido sobre o que o texto está falando, descrito anteriormente. Então para não ficar repetitivo, eu colocaria desta forma.
No mais, entendi perfeitamente!
Ensaio 2 (03/24/17)
Evolution is propelled for different forces. Nevertheless, it is usually associated only with one of them, the natural selection. That, as result of the big influence of Darwin in the understanding of the evolution theory. In this way, it can be difficult to think in evolution as result of other mechanisms than those inherent to adaptive values. However, between the processes that propel evolution, there are one of them more likely to occur, the genetic drift. The genetic drift is non selection-driven. Instead, it generates variation in allele frequency in a stochastic way, without any allele’s adaptive value. So that, it can result in the loss or fixation of alleles, even if they are harmless or not for populations. Today it is known, that there are so many variations generated by genetic drift, that most of them should be neutral. On the hand, variations by natural selection are less frequent. But, commonly with a greater probability of cause impact on the evolutionary history of organisms. Whatever the mechanism of evolution of which we speak, it is important to highlight they are not mutually exclusive. So, the interaction of different evolutionary forces influences the way in which history of populations is shaped.
Comentarios de Stefany A. de Angelis:
Consegui encontrar em seu texto os padrões de redação que estamos aprendendo em sala. Isso é muito bom. Torna o texto bem mais claro.
Só falta citas referências agora. Tanto no texto, para informar de onde veio aquela ideia, teoria ou hipótese. E também a referência no final, complementando a informação citada na redação.
Ensaio 3 (31/17/17)
Audience: graduate students
The effective population size can be defined as the part of an ecological population that contributes genetically to the next generation. That means, that if all organisms of a populations transmit their genetic information to next generation by reproduction, the effective population size will be equal to the number of organisms that we can count directly in the population. However, in order the aforementioned occurs, the population should met certain requirements. For example, the number of males and females should be equal, all the organisms should have the same opportunity to reproduce themselves, and the generations must not have overlapping reproduction. Since it is impossible to fulfill all those assumptions. A long the years it has been developed different methods to estimate that parameter. Each one of them adapted to “correct” the assumption that it is violated.