Figure 5.—

Schematic of the two possible ancestral relationships among Cf-9 (9C), 9D, and 9DC. Arrowed boxes represent complete Hcr9's; Cf-9 sequences are shaded; 9D sequences are solid; open boxes, unknown Hcr9 sequences; solid triangles, LipoxygenaseC exons. Diagonal crossed lines, (unequal) recombination points; arrows point toward one of the possible recombination products. All recombinations are shown in a homozygous genotype. (A) A single intragenic recombination between 9D and Cf-9 could result in the 9DC gene. (B) The Cf-9 and 9D genes can be generated only from two 9DC genes via two independent unequal recombinations at identical positions within each of these 9DC genes. Recombination of 9DC1 with an unknown Hcr9 that carries 5′ Cf-9-like sequences would result in Cf-9. Recombination between 9DC2 and an unknown Hcr9 that carries 3′ 9D-like sequences would generate 9D.