Global Journal of Human Social Science, G: Linguistics and Education, Volume 21 Issue 14

in the academy allows the student to learn recent conceptions that may contribute to or modify knowledge based on the school curriculum. In this aspect, the pedagogical practice can present itself as a response to scientific conceptions, connected to current paradigms. Therefore, the genetic paradigm can be placed at the center of controversies. Genetics, as part of the biology occupies in understanding the mechanisms and laws that account for the transmission of the characteristics of living things through the generations. The genesis of genetics in modern science stems from the studies of the Austrian Gregor Mendel, around 1860. And, with scientific and technological advances, genetics encompasses studies both in the area of Cell Biology and Molecular Biology, which comprises acid molecules deoxyribonucleic (DNA) and structural part of chromosomes, where genes are found, as responsible for information for protein synthesis. Regarding the study of the functioning of genes in cell nuclei, in 1940, the English biologist Conrad Hal Waddington (1905-1975), presented the concept of epigenetics in his book Organizers and genes (SANTOS, 2015). Epigenetics is a metaphor used to explain the different processes that a cell undergoes in its gene activity in embryonic development and in each cell division. It is worth noting that the origin of the term "epigenetics" occurred to Aristotle, from their empirical observations on the embryonic development of animals, to refer to the origin of a living being. Such a conception, called vitalist, was accepted until the 18th century. However, it was from the studies of Descartes and Isaac Newton that they started to adopt a material explanation for the origin of a living being linked to organic molecules. (CANGUILHEM, et al, 2003) The understanding of how, in fact, the representation of complex order characteristics in living organisms is characterized, according to Oliveira and Muller (2015), as a third historical moment in twentieth- century biology. For these authors, at first, Biology was strongly influenced by creationist ideas, even with the advent of the Theory of Evolution; in a second moment, by Newton's mechanistic ideas and, in a third moment, when other theorists, including Henri Atlan, propose the theory of complexity for a broader approach to biological knowledge. As Henri Atlan (2013) emphasizes, epigenetic mechanisms act to change the way in which the accessibility of chromatin for transcriptional regulation in the modification of DNA and nucleosomes occurs. Such mechanisms are essential for cell development. In addition, gene regulation is influenced by the environment and modifies over time, as shown by current studies and performed in the field of epigenetics. According to Silva and Duarte (2016, p. 438-439): Epigenetic mutations occur quite differently from genetic mutations. They are the product of the silencing or activation of a gene and not the change in the order of nitrogenous bases; they just turn genes on and off. Furthermore, epigenetic mutations are always targeted, responding to environmental changes. Some forms of epigenetic mutation can pass on to offspring, functioning as a genetic mutation; but, unlike the latter, they can be reversible. Thus, this very current epigenetic concept modifies some bases of molecular biology in its central dogma: DNA - RNA - protein, seen in a linear fashion, since different DNA fragments, in combination with others, can generate different proteins in the organism, considering the exons, the introns and the biological phenomenon called splicing. This new fact for Biology has led to genetic research, opposing the idea of linearity of the DNA molecule and, at the same time, demonstrating a character of complexity, fundamental in the teaching of science in the 21st century (MORIN, 2006). DNA is a polynucleotide that is found with four different species of nucleotides, different from each other by their nitrogen base. Such bases are: adenine (A), thymine (T), guanine (G) and cytosine (C). It is from the structure of the concept of DNA that Atlan (2006) attributes the “Information Theory” in order to present the implications involved in the study of the gene. So, a DNA molecule is made up of thousands of nucleotides, which are organized like written messages of four symbols. Still, following the same criteria, a protein is a polymer made up of millions of amino acids. There are 20 (twenty) different amino acids. So, a protein organizes itself as messages written in 20 (twenty) symbols. This means that “there is a univocal correspondence between the structure of a DNA molecule, determined by the sequence of its bases, and that of a protein, determined by the sequence of its amino acids” (ATLAN, 2006, p. 122). Under the focus that the amino acid sequence is encoded in the DNA base sequence, effecting the protein synthesis, Atlan (2006) problematizes two aspects: one refers to the coding of messages in an alphabet of 20 (twenty) symbols, in messages with an alphabet of 4 (four) symbols, and another in relation to the coding methods carried out in nature, if they are really the same in all living organisms. In this respect, he claims that the coding is really the same in all organisms, which evidences, according to him, what we call the genetic code, since it constitutes a coding method common to all organisms. However, the author emphasizes that encoding should not be confused with programming (ATLAN, 2013). It was in the 1960s that Molecular Biology made great discoveries and started to adopt the metaphors commonly known in the field of “information” and “cybernetics”. Studies on the DNA start to present concepts from the structure of DNA findings; its role in reproduction; those genes are DNA molecules and their duplication and transmission of information both within © 2021 Global Journals Volume XXI Issue XIV Version I 14 ( G ) Global Journal of Human Social Science - Year 2021 Conceptions about Teaching DNA in Basic Education: A Reading based on Henri Atlan