"Man is but a worm" was the title of a famous caricature of Darwin's ideas in Victorian England. Now, 120 years later, a molecular analysis of mysterious marine creatures unexpectedly reveals our cousins as worms, indeed.
An international team of researchers, including a neuroscientist from the University of Florida, has produced more evidence that people have a close evolutionary connection with tiny, flatworm-like organisms scientifically known as "Acoelomorphs."
The research in the Thursday (Feb. 10) issue of Nature offers insights into brain development and human diseases, possibly shedding light on animal models used to study development of nerve cells and complex neurodegenerative diseases such as Alzheimer's and Parkinson's.
"It was like looking under a rock and finding something unexpected," said Leonid L. Moroz, a professor in the department of neuroscience with the UF College of Medicine. "We've known there were very unusual twists in the evolution of the complex brains, but this suggests the independent evolution of complex brains in our lineage versus invertebrates, for example, in lineages leading to the octopus or the honeybee."
The latest research indicates that of the five animal phyla, the highest classification in our evolutionary neighborhood, four contain worms.
But none are anatomically simpler than "acoels," which have no brains or centralized nervous systems. Less than a few millimeters in size, acoels are little more than tiny bags of cells that breathe through their skin and digest food by surrounding it.
Comparing extensive genome-wide data, mitochondrial genes and tiny signaling nucleic acids called microRNAs, the researchers hailing from six countries determined a strong possibility that acoels and their kin are "sisters" to another peculiar type of marine worm from northern seas, called Xenoturbella.
From there, like playing "Six Degrees of Kevin Bacon," the branc
|Contact: John Pastor|
University of Florida