Humans, mice, zebrafish, and most likely other animals, share enhancers — DNA regions that help to regulate gene expression and evolve rapidly — with Amphimedon queenslandica, a species of sea sponge from the Great Barrier Reef, according to new research.
“Some elements of the human genome — an organism’s complete set of DNA — functioned in the same way as the sponge,” said senior author Professor Bernie Degnan, a researcher at the University of Queensland.
“Incredibly, these elements have been preserved across 700 million years of evolution.”
“This mechanism drives gene expression, which is key to species diversity across the animal kingdom.”
“It’s an important piece of a puzzle over many millions of years, and will feed into future research studies across the medical, technology and life sciences fields.”
“This is a fundamental discovery in evolution and the understanding of genetic diseases, which we never imagined was possible,” said lead author Dr. Emily Wong, a researcher at the Victor Chang Cardiac Research Institute and the University of New South Wales.
“It was such a far-fetched idea to begin with, but we had nothing to lose so we went for it.”
Professor Degnan, Dr. Wong and their colleagues collected sea sponge samples from the Great Barrier Reef.
They then extracted DNA samples from the specimens and injected them into a single cell from a zebrafish embryo.
Without harming the zebrafish, they repeated the process with hundreds of embryos, inserting small DNA samples from humans and mice as well.
Despite a lack of similarity between sponge and human DNA, they identified a similar set of genomic instructions that controls gene expression in both organisms.
“We are interested in an important class of these regions called enhancers,” Dr. Wong said.
“Trying to find these regions based on the genome sequence alone is like looking for a light switch in a pitch-black room.”
“And that’s why, up to this point, there has not been a single example of a DNA sequence enhancer that has been found to be conserved across the animal kingdom.”
“Our team focused on an ancient gene that is important in our nervous system but which also gave rise to a gene critical in heart development, and the findings will also drive biomedical research and future healthcare benefits too,” said co-author Dr. Mathias Francois, a researcher at the University of Queensland and Centenary Institute.
“The more we know about how our genes are wired, the better we are able to develop new treatments for diseases.”
The study was published in the journal Science.
Emily S. Wong et al. 2020. Deep conservation of the enhancer regulatory code in animals. Science 370 (6517): eaax8137; doi: 10.1126/science.aax8137