Genetic testing
College students enrolled in basic genetics courses often bring with them deep-rooted conceptual difficulties about fundamental genetic principles. Even among students majoring in the biological sciences, these erroneous concepts can be surprisingly difficult to dislodge, according to two biologists involved in science education research.
Michelle Smith of the University of Maine, and Jennifer Knight of the University of Colorado administered a 25-question, multiple-choice Genetics Concepts Assessment to undergraduate students enrolled in basic genetics courses at the University of Colorado in Boulder, both as a pretest on the first day of classes and as a posttest as part of the final exam. A total of 750 students took the assessment both times and were included in the data set for the study.
The researchers found that nine of the 25 questions generated the most incorrect post-test responses, reflecting fundamental student misunderstanding in three broad concept areas: genetic content and genetic code; the nature of mutations and their effects; and the process and results of meiosis, including probability calculations. A number of these questions address “very basic concepts” that most college-bound students would have encountered in high school science classes, the authors write. They also found that a surprising number of students, both biology majors and non-majors, persisted in answering these nine questions incorrectly in the post-test, even after instructors had addressed the information over the term in lectures, homework and exams. Each of the nine questions had a “most common incorrect answer” – or MCIA – that was selected by a high percentage of students who answered incorrectly. “If a student selects the MCIA on the pretest and incorrectly answers the same question on the posttest, he or she will most likely select the MCIA again,” Knight and Smith wrote in the journal Genetics. “Our results show that for students who answer the MCIA on both pre- and posttests, the incorrect answers may represent actual misconceptions that are resistant to change. Furthermore, such misconceptions can prevent students from learning a concept that is consistent with what scientific data suggest to be true.” The authors encourage educators to systematically identify fundamental student misconceptions about genetics and correct them with a variety of techniques throughout the academic semester, including reflecting on current scientific knowledge, using contextual examples for discussion of concepts, and asking students to synthesize established scientific knowledge with emerging ideas. They also recommend that instructors develop a teaching system of materials and methods grounded in educational data that will help students successfully overcome misconceptions early on and achieve a foundational understanding of genetic principles.
