The results of a study of the meiosis models utilized by individuals at varying levels of expertise while reasoning about the process of meiosis are presented. Based on these results, the issues of sources of misconceptions/difficulties and the construction of a sound understanding of meiosis are discussed. Five individuals from each of three levels of expertise in genetics participated in this study. The expert group consisted of one university professor, two visiting lecturers, and two advanced graduate students from the University of California Berkeley (UCB) Department of Genetics. The experienced novices were five senior undergraduate genetics honor students at UCB who had already completed their core genetics courses and who were concurrently working in genetics research. The inexperienced novices were five UCB undergraduate biology majors concurrently enrolled in an introductory genetics course. The five inexperienced novices had all scored above 87% on their first midterm exam and were interviewed following classroom exposure to meiosis. Three aspects of the participants' overall meiosis models--common correct features, misconceptions, and model qualities--are elaborated on. (32 references) (KR)