As Symbol as That: Inconsistencies in Symbol Systems of Alleles in Textbooks, and Students’ Justifications for Them

Abstract

In genetics education, symbols are used for alleles to visualize them and to explain probabilities of progeny and inheritance paradigms. In this study, we identified symbol systems used in genetics textbooks and the justifications provided for changes in the symbol systems. Moreover, we wanted to understand how students justify the use of different symbol systems when solving genetics problems. We analyzed eight textbooks from three different countries worldwide. We then presented a genetics problem to eight 9th-grade students and probed their justifications for the use of different symbol systems. Our findings showed that there is no one conventional symbol system in textbooks; instead, symbol systems are altered along and within textbooks according to the genetic context. More importantly, this alteration is not accompanied by any explicit explanation for the alteration. Student interviews revealed that some students were able to identify the genetic context of each symbol system, whereas others, who were unable to do so, provided justifications based on different non-genetics-related reasons. We discuss the implications of our analysis for how multiple symbol systems should be presented in textbooks, and how they should be introduced in the classroom.

An Analysis of the Visual Representation of Redox Reactions in Secondary Chemistry Textbooks from Different Chinese Communities

“…Since chemistry textbooks are the medium between chemistry and the learner [42], textbook analysis is gaining increasing interest in chemistry education in general (e.g., [2,25,43]), and in this journal in particular (e.g., [44,45]). Textbook analysis of visual representations can help to ensure that they are better used in future textbooks.…”

Explanatory black boxes and mechanistic reasoning

“…In fact, when these “genetics black boxes” were described to students as information they may unpack to solve a given problem, ninth grade students justified their choice of the black boxes they wished to unpack in relation to the problem they had to solve (Livni‐Alcasid & Haskel‐Ittah, 2022). Namely, these students could link the goal of an explanation to whether certain black boxes needs to be unpacked or not.…”