To investigate the origins of vertebrates and other features of cephalochordate biology, a team of researchers led by Dr. Linda Holland of the Scripps Institution of Oceanography searched the amphioxus genome for specific genes, gene families, and DNA elements that could shed light on chordate biology and evolution. The analysis identified a number of features of amphioxus that are conserved with vertebrates, as well as some that are unique. In addition to new insights on development, cell signaling, immunity, and endocrine systems, Holland and colleagues identified several DNA regulatory elements conserved between amphioxus and humans. Three conserved elements from two human paralogs and a single amphioxus homolog were all shown to drive gene expression in both amphioxus and the mouse. “This is the widest phylogenetic distance to date over which both the sequence and function of cis-regulatory enhancers has been found to be conserved,” explains Holland. The group concluded that while amphioxus displays many characteristics of a pre-vertebrate ancestor, it also has specialized features that have developed since diverging from chordate ancestors.
Primitive Pre Vertebrates Still Evolving
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