Minute mutations – first described in Drosophila as a class of mutants with remarkably similar phenotypes – are mutations in ribosomal proteins that have provided insights into cell autonomy,compartmental development and cell competition. While numerous in fruit flies, Minutes are apparently rare in mammals, and, on p. 3907, Oliver et al. provide the first detailed characterisation of a mammalian Minute. The semi-dominant mutation belly spot and tail (Bst)affects pigmentation, somitogenesis and retinal cell fate determination, and as the researchers report, is caused by an intronic deletion in the Rpl24 riboprotein gene, affecting Rpl24 mRNA splicing and disrupting ribosome biogenesis, protein synthesis and cell proliferation. Furthermore, in chimeras, Bst/+ cells grow more slowly than wild-type cells, reminiscent of the cell competition effect observed in Minute Drosophila cells. These findings highlight the possible roles of riboprotein mutations in human growth, skeletal and ocular diseases.