2 Scientists May Have Discovered How the World's First Ever Animal Appeared
The rich and diverse animal kingdom, as the world knows it, descended from a common ancestor, which has always been a mystery until now.
The duo behind a new research published on Nature found a way to reconstruct the genome of the first ever animal, which is believed to have lived 650 million years ago. This leads to the discovery of exciting new information about the earliest days of the animal kingdom.
The research reveals that an evolutionary burst of new genes may have marked the beginning of the animal kingdom. The single-celled ancestors could have spawned into creatures with complex bodies made of different kinds of cells. The new genes were proven to be very durable with 55 percent already present in the first animal.
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"The big surprise was how many of them there were," University of Essex evolutionary biologist Jordi Paps, who is also the co-author of the new study, said.
As to how Paps and co-author Peter W.H. Holland, a zoologist at the University of Oxford, arrived at the conclusion, they put together an extensive animal family tree and selected 62 species, which included the species of humans, to study further.
The pair searched the DNA of the organisms by indexing the genes that encode proteins and the molecules that cause chemical reactions in the body, assembling the structure.
The researchers ended up with nearly 1.5 million genes in total and proceeded to estimate when the first step of evolution kicked in with these. They discovered that 6,331 genes were present in the common ancestor of all living animals.
They found out that many of those genes have already existed prior to the existence of the animals themselves. Some, which are discovered to be essential to the basic mechanism of all living things such as copying DNA, made their first step towards evolution billions of years ago. Other genes only surfaced more recently and are still found today in close single-celled relatives.
All this reveals that when animals first came into existence, the old genes had to make something new. For single-celled protozoans, it is using some genes to make proteins that let them cluster together into tiny colonies. In animals, the genes allowed for the cells to bond themselves permanently together in order to build a body.
Breaking these genes further down, Dr. Paps and Dr. Holland determined that 1,189 of the genes found in the first ever animal are not even found in the closest known single-celled relatives, which led them to believe that the new genes may have evolved into proto-animals.
How that was made possible, Dr. Paps posits that this is either due to a random string of DNA with no function mutated and started producing a protein or an existing gene accidentally made a duplicate that underwent more mutations that led to the production of a new kind of protein while the other copy functioned the same way as the original gene.
In line with this, Dr. Paps speculates that the burst of new genes in early animals may be the result of the environment triggering a lot of mutations. She believes there is also a chance that the proto-animals gradually accumulated all the new genes over hundreds of millions of years.
The pair also discerned that a number of the genes developed by proto-animals are linked to cancer in the sense that many of them keep cells from working together harmoniously so that when they mutate, cells could end up multiplying uncontrollably.
