Study calls for a shift in understanding of how complex cell
types evolved
In a study that compares the genomes of aquatic life forms,
researchers have found evidence to shuffle the branches of the tree of life.
For more than a century, scientists thought that complex cell types, like
neurons and muscles, evolved only once, after simple animals that lack these
cell types branched from the rest of animals on the evolutionary tree. A team
of researchers from the National Human Genome Research Institute (NHGRI), part
of the National Institutes of Health, has provided new evidence from the
genomic study of a ctenophore species - a comb jelly - that challenges this
long-held view.