Evolution of the homeobox gene content of chordates

Retention and loss of homeobox families in chordates (adapted from Holland et al (2008) Genome Research 18,1100-1111).

The recently sequenced genome of amphioxus (Branchiostoma floridae), a basal lineage of chordates, is proving to be immensely valuable for revealing characteristics of the organisation of the genomes of the chordate and vertebrate ancestors. Amphioxus has retained the full complement of homeobox gene families that are inferred to have been present in the chordate ancestor.

Other chordate lineages have lost some of these gene families. Amphioxus thus provides us with a system with which to understand how these important developmental control genes have been involved in the evolution of the animal lineage containing humans.

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