Yoshimoto et al. (1990) found that the amino acid sequence of human reticulocyte 15-lipoxygenase (Sigal et al., 1988) showed 86% identity with that of porcine leukocyte 12-lipoxygenase. Sigal et al. (1988) found 61% sequence similarity between 15-lipoxygenase and 5-lipoxygenase. This suggests that in the human 12-lipoxygenase is more closely related evolutionarily to 15-lipoxygenase than to 5-lipoxygenase, even though the comparisons are made between human and porcine enzymes. By PCR analysis of a human-hamster somatic hybrid DNA panel, Funk et al. (1992) demonstrated that genes for 12-lipoxygenase and 15-lipoxygenase are located on human chromosome 17, whereas the most unrelated lipoxygenase (5-lipoxygenase) was mapped to chromosome 10.