The development of expertise in genetic pedigree problem solving

Genetic disorders are to some extent predictable and are therefore preventable through genetic counselling. One aspect of the role of genetic counsellors is the construction and analysis of genetic pedigrees which are an important tool in the counselling This thesis process. reports on a study of the development of expertise in pedigree analysis skills. The purpose of this research programme was to compare experts and students' use of genetics knowledge in testing inheritance hypotheses during the solution of genetic pedigree problems, and to develop and implement educational interventions to train novice geneticists in the use of experts' hypothesis testing strategies. Expert groups were comprised of specialist university genetics lecturers and genetic counsellors; student groups were comprised of first and third year undergraduate genetics students. The research programme was comprised of five studies. Think-aloud protocol data from the first study indicated that experts obtained more correct answers and produced more conclusive solutions than students. Experts were more effective in their hypothesis testing than students as they were able to recognize and correctly interpret more patterns of inheritance than students, and were more systematic in their falsification of alternative hypotheses. An expert consensus study produced an optimal solution for each of the problems. These solutions were characterized by a two step solution process which quickly reduced the set of inheritance hypotheses. In the first step, patterns of affected and unaffected individuals in the pedigree were used as cues to falsify either both recessive or both dominant modes of inheritance. The second step involved the use of cues to discriminate between the remaining autosomal and X-linked inheritance hypotheses. Written tests used in the third study demonstrated that most novice students lacked the genetics knowledge needed to test hypotheses related to X-linked modes of inheritance. Case study data from a fourth study showed that students' inconclusive and incorrect solutions to problems could be directly traced to a failure to recognize and correctly interpret X-linkage cues. In the fifth study a treatment group of novices instructed in the knowledge and strategies used by experts obtained more correct answers and produced more conclusive solutions to pedigree problems than a control group exposed to traditional instruction. The main charter of institutions of higher education is the development of expertise. This research programme has demonstrated the pedagogic utility of the expert-novice paradigm in achieving this educational goal