Abstract:

Teaching genetics often poses the challenge that students solve Mendelian probability problems mechanically, without understanding the underlying biological process that generates gamete diversity. This paper presented the design and implementation of a didactic sequence based on active learning, aimed at helping students associate meiotic events with the laws of segregation and independent assortment of genes. The methodology was structured into four progressive stages. Initially, a Learn-Before-Lecture (LBL) strategy was used to ensure understanding of DNA variation during the cell cycle. Subsequently, students engaged in hands-on modeling activities using moldable materials to represent gamete formation in 2n=2 and 2n=4 cells. This enabled visualization of abstract concepts such as homologous chromosomes, loci, and alleles. The sequence integrated the dichotomous method and the Product Law to connect cellular models with probability calculations in dihybrid crosses. Qualitative results indicated that students successfully corrected misconceptions regarding gene location and the distinction between single and duplicated chromosomes. Furthermore, in their reflections, students correctly identified the random arrangement of chromosomes in Metaphase I as the key mechanism for genetic variability. Quantitatively, the final evaluation revealed the strategy's high effectiveness, with success rates ranging from 78.6% to 100% on critical questions regarding the identification of meiotic phases and allelic segregation. It was concluded that manipulating physical models combined with theoretical reflection facilitated a deep understanding of biological inheritance beyond mere statistics.

Keywords:

Meiosis, Genetic Segregation, Mendel's Laws, Active Learning, Didactic Models.