The purpose of this study was to investigate the comparative effects of prediction/discussion-based learning cycle (HPD-LC), conceptual change text (CCT), and traditional instructions (TI) on 8th grade students&rsquo / understanding of genetics concepts and on their perceived motivation and perceived use of learning strategies. This study was carried out during 2006-2007 fall semester at a public elementary school in Ankara. A total of eighty-one 8th grade students from three intact classes were involved in the quantitative part of this study. Students in the first and second experimental groups instructed with HPD-LC and CCT, respectively. The students in control group received TI. In the qualitative part, pre- and post-instructional interviews held with six students were interpreted by using a multidimensional interpretive framework of conceptual change. In this study the Genetics Concept Test was administered as pre-test, post-test, and delayed post-test in order to examine the effects of instructional strategies on students&rsquo / genetics understanding and retention. The Motivated Strategies for Learning Questionnaire was administered as pre-test and post-test to examine the effects of instructional strategies on students&rsquo / motivation and use of learning strategies. The results of mixed between-within subjects ANOVA revealed that students in both experimental groups understood the genetics concepts and retained their knowledge significantly better than students in control group. One-way MANOVA results revealed that HPD-LC students used elaboration strategies significantly more than CCT students. Interview analysis by considering ontological, epistemological, and social/affective perspectives of conceptual change indicated that some students from each group underwent conceptual change concerning the genetics concepts.