Estudo das concepções de licenciandos de ciências biológicas sobre a relação de dominância e recessividade

Abstract

The research presented in this paper aimed to investigate the conceptions of students of higher education on dominance and recessivity, and relate to the construction of knowledge in genetics in this group. The target audience was graduates of the course of Biological Sciences of the Federal University of Minas Gerais and the methodology included analyzes of a discursive exercise and two questionnaires on the allelic interaction of dominance and recessivity related to molecular processes. An analysis was also made of two didactic books indicated in the bibliography of the basic subjects of Genetics of the course in order to verify how the introductory content of dominance and recessivity is presented. Through quantitative and qualitative analysis - discursive textual analysis - it was observed that the students had difficulty to understand about the expression of recessive alleles. The most common explanations for dominance in the questionnaires were: "dominant allele inhibits the recessive allele," "recessive allele produces no products," and "recessive allele produces low numbers." Students who have shown understanding about molecular concepts related to allelic interaction, such as transcription, translation, protein production and structural differences of alleles, have explained that the recessive allele is transcribed. But many students went wrong by pointing out that the allele is not translated or encodes proteins in low amounts. Other students, for example, have not been able to explain in detail the stages of transcription and translation, tending to explain that the dominant allele inhibits the recessive. The textbooks analyzed presented the Mendelian inheritance and the concepts of dominance and recessivity with no emphasis on the modern contextualization of molecular biology. In addition, it was seen that words such as "suppressed" and "masked" are used to explain the dominant and recessive terms in the phenotype in a context that may bring confusion about the concept of dominance and recessivity, leading readers to interpret that the dominant allele inhibits the recessive allele. Although there have been excerpts from examples of diseases at the molecular level in later chapters, the chapters dealing with molecular biology do not reflect on gene expression taking into account the allelic interaction of diploid models. One of the main conclusions of this study is that this topic should be of interest to the professor of genetics of higher education who, by being attentive to teaching this content relating the themes of transcription, translation, could collaborate so that the student understood the content of integral form and connected.