Figure 16.7   Phylogeny of the basal fi shes. One major genome duplication event was apparently associated with the origin of jaws. When the fossil groups (open lines) are omitted, there is a large morphological and genomic leap from jawless lampreys and hagfi shes; when the fossil groups are included, as here, the transition appear much more gradual. The timing of the genome duplication events is uncertain, and falls within the area of the gray box. The number of families within each living and fossil group is shown by the shaded vertical bars. (Courtesy of Phil Donoghue.)

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