Fig. 2.

Positional cloning of naked caryopsis gene (nud) in barley. (A) High-resolution genetic map and physical map. Thick lines show four BAC clones sequenced. The recombinant numbers are shown below the genetic map. (B) Structural differences near the nud locus between covered barley (Haruna Nijo) and naked barley (Kobinkatagi). Black arrows indicate the appropriate location of PCR primers. (C) Structure of the Haruna Nijo Nud gene (standard) and nucleotide changes found in two radiation-induced naked mutant alleles, nud1.b (red arrow) and nud1.c (red arrowhead). Boxes indicate exons, and the black bar between the boxes shows an intron. Deduced functionally important domain/motif(s) are colored. The motif names, “mm” (middle motif) and “cm” (C-terminal motif), follow Aharoni et al. (21). The asterisk indicates a stop codon resulting from the frame shift (F.S.). Natural allelic variations found among 33 covered lines are also indicated by green arrows (synonymous substitutions) and black arrows (nonsynonymous substitutions).