Weird, Brainless Worm May Be Humankind's Ancestor

Everyone's got that one weird relative, but a tiny creature thought to be mankind's earliest ancestor might just be the weirdest of them all.

Swedish scientists have announced new findings on the so-called "paradox worm," or Xenoturbella bocki. The simple-bodied organism has no brain, no sex organs and no vital organs, yet new evidence makes a compelling case that it might be the "progenitor of mankind," according to a written statement from Sweden's University of Gothenburg.

The worm, which measures 1 centimeter in length when fully grown, is regarded by some researchers as an important biological link between many species. Although its status has been debated by zoologists, a new study published by researchers at the the university's Centre for Marine Research and the Gothenburg Natural History Museum provides evidence that the worm might belong to a branch of the animal family tree called deuterostomes, of which humans are also members.

"So maybe we're more closely related to the Xenoturbella bocki worm, which doesn't have a brain, than we are to lobsters and flies, for example," study co-author Matthias Obst said in the statement.

While the paradox worm may seem bizarre, its evolutionary relationship to people might be crucial in advancing important research. The researchers found that the worm's early embryonic development is similar to that of humans, which could help answer questions about how human organs are formed.

In an email to The Huffington Post, Obst clarified that although the worm is related to humans and other deuterostomes, it might occupy its own "evolutionary branch." Because of that special vantage point, Obst said that the worm could demonstrate "potentially unique mechanisms and processes related to aging [and] longevity, as well as regeneration of organs and tissues" that could then be applied to human stem cell research and other biomedical technology.

During research, the Gothenburg team was able to isolate newborn specimens of the worm for the first time. Using a process for amplifying and copying DNA known as polymerase chain reaction (PCR), the team was able to replicate the worm's DNA using samples extracted from eggs and embryos.

The study notes that further DNA sequence analysis is needed to properly establish whether or not the paradox worm constitutes its own branch among the deuterostomes.

Deuterostomes, a name derived from the Greek meaning "second mouth," are distinguished by early embryonic development in which the tiny cell cluster's first opening, called the blastopore, becomes an anus rather than a mouth. This is trait is common to four phyla of animals, which encompasses diverse live forms, from sea cucumbers right on up to chordates -- animals with a spinal chord, including humans.

The research, "Xenoturbella bocki exhibits direct development with similarities to Acoelomorpha," was published in Nature Communications in February 2013.