Credit: AFP

The recent breakthrough finding that proves humans share similar gene pool with sea sponges - which existed more than 600 millions ago - has triggered a change in a the long-held views of the scientific communities that the first animals were nothing but simple ball of cells.

The genomic innovations that are foundational for complex present animal life essentially go back further in time, predating the Cambrian explosion by tens, if not hundreds of millions of years.

An international team of scientists, led by Professor Bernard Degnan from UQ's School of Biological Sciences have started the process of genome sequencing of the first marine animal found on Australian waters.

All contemporary animals, from sea sponges and corals to butterflies and humans evolved from ancient and long-extinct ancestors, stated the study report of on sea sponges published in Nature.

According to Prof Degnan, the incredibly ancient ancestor carried the same basic building blocks for multicellular form and function that still sits at the heart of all living animals, including humans.

The findings that confirmed sponges and humans and their common ancient ancestor share an amazing number of genes - are entirely unexpected as sea sponges are such simple organisms, said Dr Degnan.

He said, It now appears that the evolution of these genes not only allowed the first animals to colonize the ancient oceans but underpinned the evolution of the full biodiversity of animals we see today.

Prof Degnan turned to genomics - the most modern of biological sciences study to uncover the ancestor, as the current records on deep animal fossil are highly incomplete.

He said, Searching for commonalities among the genomes of modern species whose lineages separated before the Cambrian period allowed me to develop a high-resolution picture of the ancestral animal genome.

He said genes and genomic features that are shared between distant species like sponges and humans are likely to be inherited from their common ancestor.

Genomics, basically allowed us to travel back at least 600 million years in time to catch a glimpse at the very first multicellular creatures to roam our oceans, said Prof Degnan.

The collaborative effort to sequence the Great Barrier Reef sponge genome by Prof Degnan with his primary research partner, Professor Dan Rokhsar started in 2003 after receiving the green light from the US Department of Energy Joint Genome Institute.

Though simple from their exterior, the sea sponges have a remarkable genome complexity - it includes all of the gene families required for the development and functioning of complex animals, including humans.

Prog Degnan said the reconstruction of the last common ancestor between humans and sponges is possible based on the comparison between both species.