Fig. 1.

Crossover of genetic material between homologous chromosomes during meiosis I. WT-GALT wild-type galactose-1-phosphate uridyltransferase enzyme gene (normal function), WT-FXN wild type frataxin gene (normal function), GAL classical galactosaemia-causing mutation in GALT, FRDA Friedreich ataxia-causing mutation in FXN