A recent study concerning our genetic background has found that acorn worms are the weirdest human species’ relatives, our genome matching reaching almost 70%.
The study was conducted at the University of California, Berkeley, to reveal the mysteries concerning our genetic ancestry by studying our sequencing of genes when compared to other animals. This research revolved around how the gills in hemichordates, or underwater worms, have evolved into the pharynx that animals possess.
The Enteropneusta, commonly known as the acorn worm, is a slimy worm that lives on the bottom of the ocean and can sometimes reach a length of 8.2 feet. When creating the genome sequence draft of the acorn worm, scientists at Berkeley have found that we have almost 70% genetic counterparts with these worms, inherited from a common ancestor.
The divergence in our genes happened over 550 million years ago when our genetic line forming the upper and lower pharynx system that we and animals use today split from the gill system that the worms possessed. Some vestigial gills that were “missed” in the evolutionary process can still be seen in some embryos of humans or other terrestrial vertebrates, some of these gill slits being kept in rare cases until infancy. They eventually disappear as the embryo forms, due to the fact that they are not entirely functional and are deemed useless for air-breathing species.
The event that created the diversity we see today in animals is known as the Cambrian explosion. This event has been carefully studied by scientists around the world through the use of genome sequencing in order to reveal our ancient common ancestors.
When comparing the genome sequence draft of the acorn worm to the drafts of over 32 different animals, including us, they discovered that we all share similarities in about 70% of it. The similarity between the pharynx system and the gills that the worms possessed is called homologous, and is more or less the same to how wing and flippers are similar to hands and paws, all starting from the same ancestral group of genes,
The other 30% of the genetic sequence of acorn worms relates to algae and bacteria and its role is to coat their cells with modified sugars. This is extremely interesting because evolution might have made a direct leap from bacteria to hemichordates, circumventing some evolutionary steps that are normally seen.
Even though acorn worms are the weirdest human species’ relatives, this does not mean they should be shunned. By studying them even further and by compiling more and more genome sequences in various chordates and non-chordates, scientists will be able to better grasp the concept of ancient evolution and eventually how life came to be on our planet.