Gut Development in Different Species is Same

A marine creature throws a strand of evidence about the similarity of process in the formation of gut by different animals.

The research study led by Dr. Andreas Hejol from the Sars International Centre for Marine Molecular Biology in Norway, shows marine penis worms developing their intestine as humans or fish.

They basically examined the formation of the gut and the expression of genes needed to form the mouth and the anus in priapulid embryos. Priapulids are an obscure group of marine worms that live in shallow waters.

"Surprisingly, priapulids form the gut like humans, fish, frogs, starfish and sea urchins -and all of them even use the same genes. It does not mean that these penis worms are now closely related to humans. Instead the fact that different animals share a common way of forming the gut suggests that the embryological origins of the human intestine and how it develops are much older than previously thought -- most likely over 500 million years, when the first bilaterally symmetric animals appeared on Earth" remarks Hejnol.

This is the first study on the entire embryonic development of these mysterious animals.

"Priapulids are important for understanding the evolution of animals, because they are thought to be among the first bilaterally symmetric animals and have changed very little since the Earth's Cambrian Period" said first author Dr José M. Martín-Duran.

The bilaterally symmetric animals have been divided into two large groups based on the difference in how the gut develops very early. The gut develops very early, when some cells move towards the inside of the embryo, usually at a defined region that is called the 'blastopore'.

"The important point is that in some animals this region becomes the mouth, while in others it becomes the anus. For more than a century, this difference has captivated scientists, but there is not a completely satisfactory explanation for it yet" explains Hejnol.

This study lays emphasis on the need to study the vast diversity of animals found in the oceans,

"Priapulids still hide a lot of secrets to unravel, which will have a great influence on our understanding of the origin of other major organs, such as the brain, blood or legs" concludes Hejnol.

The study was featured online on October 25 in the journal Current Biology.