Confusing chromosome number and structure: a common student error

Abstract

Genetics has long been recognized as one of the most important and difficult-to-learn components of the basic biology curriculum. In this paper, I report on a common and rather tenacious student misconception about chromosomes, an accurate understanding of which is of central importance to understanding transmission genetics. Specifically, students often believe that chromosome structure is a function of chromosome number or ploidy. Although common, the presence of this misconception in students' understanding of chromosomes can be quite elusive. Several aspects of standard genetics instruction are cited as potential sources of the ploidy/structure misconception and implications for instruction are discussed.