Frequency distribution of total leaf number for an F2 population derived from a cross of Van-0 with Ler, grown in long days. Frequency distribution of total leaf number for an F2 population derived from a cross of Van-0 with Ler, grown in long days. Shaded bars indicate individuals homozygous for the Van-0 allele of HU13, a marker close to FLC. Flowering-time ranges and means of the parents and F1 hybrid are denoted by arrows and horizontal lines, respectively. Jonathan D. Werner et al. Genetics 2005;170:1197-1207 Genetics Society of America