The sea sponge helps scientists unravel the 700-million-year-old mystery of evolution

A gelatinous sea sponge helped shed light on an elusive part of the human genome, with implications for biomedical research and healthcare.

Australian scientists have found that humans, and most likely the entire animal kingdom, share important genetic mechanisms with a gelatinous sea sponge that comes from the Great Barrier Reef.

Posted in Science today, research reveals that certain elements of the human genome – an organism’s complete set of DNA – function in the same way as the prehistoric sea sponge. This mechanism, which drives gene expression, key to species diversity in the animal kingdom, has thus been preserved through 700 million years of evolution.

UNSW scientist Dr. Emily Wong, who is based at the Victor Chang Cardiac Research Institute, says unraveling a mystery of this magnitude is significant.

“This is a fundamental breakthrough in the evolution and understanding of genetic diseases that we never imagined was possible. It was such a far-fetched idea to begin with, but we had nothing to lose, so we put in the effort,” Dr. Wong says. .

“We collected sea sponge samples from the Great Barrier Reef, near Herron Island. At the University of Queensland, we extracted DNA samples from the sea sponge and injected them into a single cell from a zebrafish embryo. Without harming them. zebrafish, we then repeated the process at the Victor Chang Cardiac Research Institute with hundreds of embryos, including small DNA samples from humans and mice. “

Dr. Wong says that despite the sponge’s lack of similarity to humans due to millions of years of evolution, the team identified a similar set of genomic instructions that controls gene expression in both organisms.

“We were blown away by the results,” says Dr. Wong.

According to the scientists, the sections of DNA responsible for controlling gene expression are notoriously difficult to find, study and understand. Although they make up a significant part of the human genome, researchers are only beginning to understand this genetic “dark matter”.

“We are interested in an important class of these regions called ‘enhancers’,” says Dr. Wong.

“Trying to find these regions based on the genome sequence alone is like looking for a light switch in a dark room. And that’s why, up to this point, there hasn’t been a single example of a sequence enhancer. DNA that has been found to be preserved throughout the animal kingdom.

“We are still a long way from a clear understanding of how DNA precisely shapes morphology in health and disease, but our work is an important step in that direction.”

Working alongside Dr. Wong is her husband and senior co-author of the article, Associate Professor Mathias Francois of the Centenary Institute.

“This work is incredibly exciting as it allows us to ‘read’ and better understand the human genome, which is an incredibly complex and ever-changing instruction manual for life,” says A / Prof. Francois. ‘The team focused on an ancient gene that is important in our nervous system, but which also gave rise to a gene that is crucial for the development of the heart.’

The findings, he says, will also guide biomedical research and future health benefits. “Being able to better interpret the human genome helps our understanding of human processes, including diseases and disorders, many of which have a genetic basis. The more we know about how our genes are connected, the better we are able to develop new treatments for illnesses.”

Marcel Dinger, professor and head of UNSW Science’s School of Biotechnology and Biomolecular Sciences (BABS), said there is so much information stored in the genome that we still don’t fully understand. “This study represents an important step towards decoding the programming language of life: the new knowledge it presents will help inform future research in the fields of medicine, technology and life sciences. It is fantastic to see such important research recognized by one of the world’s most prestigious scientific scientists. journals – this truly supports our ambition to be the best molecular bioscience school in Australia. ”