sciencetech-blog

comments

While humans have been around for about 2.5 million years, the beating of our hearts is controlled by something much older.

Scientists have uncovered an ancient molecular pathway that they believe may be between 700 million to a billion years old.

The discovery was made after researchers in Pennsylvania studied the evolution of the nervous and muscular systems of a starlet sea anemone.

Scroll down for video

Scientists have uncovered an ancient molecular pathway for the human heart that they believe may be between 700 million to a billion years old.The discovery was made after researchers in Pennsylvania studied the evolution of the nervous and muscular systems of a starlet sea anemone. Pictured is an anemone embryo

The group at Penn State University wanted to find the genes that control certain traits in these systems.

Sea anemones have nervous systems that allow them to coordinate movement and respond to their surroundings, but do not have a brain or any other analogous organs.

In a study recently, the Jegla Lab identified in the sea anemone's movement the same gene family that is responsible for the slow-wave contractions of the human heart. 

Human heart beats using nearly billion-year-old molecular...

After cloning the genes, the researchers found that its function remained relatively unchanged since the time of humans' and cnidarians' divergence from their common ancestor almost a billion years ago.

Cnidarians are an ancient group that, in addition to sea anemones, include animals such as jellyfish and corals.

'This discovery, shows that at least some of the molecular mechanisms through which we control electrical activity in things like the heart evolved in some of the earliest animals, long before the existence of hearts or even cardiac tissue,' said Professor Tim Jegla.

'This fits a broad pattern we're finding that almost all the major signalling systems used in our brains and muscles evolved hundreds of millions of years ago in an ancestor of bilaterians

'It appears that a lot of the signalling that we do in our complex neuromuscular systems is based on pre-existing programs that are just adapted to our specific physiological needs.'

According to Professor Jegla, the starlet sea anemone is in essence an animal that's as evolutionarily far away from humans as possible while still sharing the same neuromuscular signalling systems.

Comparisons of humans and cnidarians reveal that only the fundamentally important mechanisms are conserved - such as those required to make a neuron or, in this case, a neuromuscular signal.

Cells in a human heart muscle contract automatically.They are even able to do this when they are grown from stem cells in a petri dish, with the cells beating on their own. Picturedds researcher Sarah Rhodes pipetting samples in the Jegla lab

'When we compare a human and a sea anemone, we're looking at somewhere between 700 million and a billion years' evolutionary separation,' said Professor Jegla.

'Anything that's not fundamentally critical to life as a mobile, multicellular animal is different. And the things we have in common were there in the nervous system of the animal we both evolved from; they were there in the ancestor of virtually all modern animal life other than sponges and comb jellies.

'Only the fundamental mechanisms are conserved. And this gives us a window into what things we have in common that are extremely important. It tells us a lot about the history of how animals evolved.'

The lab is now moving beyond the simple cellular processes to try and determine how brains were formed.

'This discovery, shows that at least some of the molecular mechanisms through which we control electrical activity in things like the heart evolved in some of the earliest animals, long before the existence of hearts or even cardiac tissue,' said Professor Tim Jegla (pictured looking at an anemone embryo)