Elephant Shark shares DNA memory system with humans

The elephant shark (Callorhinchus milii) commonly used in the fish and chip dish is known to be very distant relative of humans.

Our ancestors split off from elephant sharks more than 460 million years ago.

At the University of Otago in New Zealand, scientists recently have discovered it has a remarkably similar DNA memory system to our own. That means fish and chips consisits of the same DNA memory which is critical to human development. 

"This memory is made up of tiny chemical tags called methylation, which are used to tell a cell what its job is and make sure it stays dedicated to it," said Tim Hore, of the Department of Anatomy at Otago, who led the research.

This DNA memory system found in the chips belongs to humans has only been found in vertebrates - animals with a backbone such as mammals, amphibians and fish. This discovery has put the researchers in dilemma about how it evolved and how farback in evolutionary time it exists.

"The fact elephant sharks also use methylation - tagging to turn off genes tells us this memory system has been around a long time," said Julian Peat of the Anatomy Department at Otago.

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"Our study identifies elephant shark as the most evolutionarily distant animal that shares this DNA-regulation system with us humans, which makes it very interesting to take a closer look at," Peat said.

"The elephant shark is something of a living fossil - it is the slowest evolving vertebrate we know of. It only lives in the cooler waters of Australia and New Zealand, so we are really fortunate to have something this valuable to science in our backyard," said Hore.

"So many things remain mysterious about the elephant shark - we do not know whether this methylation memory persists across generations, or if it contributes to howgender is decided," Hore added.

The mystery still remains about its history but the scientist have already engaged themselves to find the real facts behind it.