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COMMON WIKIMEDIA
The amphimedon queenslandica is a marine sponge native to the Great Barrier Reef.
Many human traits, such as height and susceptibility to disease, depend on genes that are encoded in our DNA. These genes are turned on and off and are further tuned by important but hard to find regions in the genome.
A particularly important class of these regions are known as enhancers, which increase the likelihood that a particular gene will be activated. Trying to find enhancers based on genome sequence alone is incredibly difficult, like finding a light switch in a dark room.
That is why, until now, there has not been a single example of a DNA sequence enhancer that has been found to be similar throughout the animal kingdom.
In a new study published in SciencesWe discovered that humans, mice, zebrafish, and probably the entire animal kingdom share enhancer regions with a marine sponge that comes from the Great Barrier Reef. Because sea sponges and humans shared a common ancestor more than 700 million years ago, this means that the functional mechanism has been conserved throughout this time.
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WHAT WE DID
Our study involved a team of researchers from the Victor Chang Heart Research Institute, the University of Queensland, the Centennial Institute, and Monash University. We started by collecting sea sponge samples from the Great Barrier Reef, near Heron Island.
At the University of Queensland, we extracted enhancer DNA from the sea sponge and injected it into a single cell of a zebrafish embryo. We found that while the enhancer sequences in the sea sponge were very different from the enhancer sequences in the zebrafish, they still worked: they successfully and consistently drove the expression of a fluorescent protein in certain types of zebrafish cells.
Based on computational predictions, we also identified and tested similar enhancers from humans and mice to demonstrate that these sequences drive the expression of a fluorescent protein in similar zebrafish cell types during development.
We found that despite the differences between the genetic sequences of sponges and humans due to millions of years of evolution, we were able to identify a similar set of genomic instructions that control gene expression in both organisms.
WHAT THIS MEANS
Our findings represent a fundamental discovery in understanding the connection between our genomes and our physical traits.
The sections of DNA that are responsible for controlling gene expression are very difficult to find, study, and understand. Although they make up an important part of the human genome, researchers are just beginning to understand this genetic “dark matter.”
The work is helping us learn to “read” and understand the human genome, which is incredibly complex. Knowing more about how our genes work will also help us understand what is wrong with disease. A better understanding of the genome will also help us understand how animals evolve. 
Emily S Wong is Chief of Regulatory Systems at the Victor Chang Heart Research Institute and a Senior Researcher at UNSW.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
