Over the past several decades, there has been a tremendous growth in our understanding of genetic phenomena and the intricate and complicated mechanisms that mediate genetic effects. Given the complexity of content in modern genetics and the inadequacy of current instructional methods and materials it seems that a more coherent and extensive approach to teaching modern genetics is needed. Learning progressions provide such an approach by describing the learning of core concepts in a domain as it unfolds over multiple grades and grade bands. In this paper we suggest a learning progression for modern genetics that spans grades 5-10. We describe the learning progression in terms of three key aspects of teaching and learning modern genetics: (1) the big ideas in modern genetics, and the knowledge and abilities that students should master by the end of compulsory education; and (2) the progression of learning that students are expected to make over several grades; and (3) the identification of learning performances and development of assessments for the proposed progression. We conclude by identifying the implications for instruction and research that stem from our analysis of the research base in genetics education, and our development of a theoretical progression for learning the big ideas in modern genetics. (Contains 2 tables and 2 notes.)