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Eugene

(61,592 posts)
Tue Apr 11, 2017, 11:07 AM Apr 2017

Your Most Distant Animal Relative Is Probably This Tiny Jelly

Source: Gizmodo

Your Most Distant Animal Relative Is Probably This Tiny Jelly

George Dvorsky
Today 9:07am

For years, a debate has raged among scientists as to which ancient creature represents the first true animal, sponges or jellies. Using a new genetic technique, a collaborative team of researchers has concluded that ctenophores—also known as comb jellies—were the first animals to appear on Earth. It’s an important step forward in this longstanding debate, but this issue is far from being resolved.

A new paper published in Nature Ecology and Evolution suggests that ancient jellies, and not sponges, represent the oldest branch of the animal family tree. The Vanderbilt University and University of Wisconsin-Madison researchers who conducted the study aren’t the first to make this claim, but they used an emerging technique to parse literally hundreds of thousands of genes, showing that comb jellies have the most ancient genome of any animal. The researchers say the method could be used to resolve other longstanding issues in evolutionary biology, but given the highly interpretative nature of their findings, it’s likely the sponge-versus-jelly debate will continue to rage on.

Decades ago, scientists slotted animals on the so-called “tree of life” by eyeballing organisms, designating the ones that appeared to be simple as more primitive in terms of their evolutionary standing. Things changed with the advent of genomics, when scientists gained the ability to read and compare the DNA of organisms and classify them accordingly. This new field, called phylogenetics, has revolutionized the way we define evolutionary relationships, but many gaps exist among the numerous branches in the tree of life—including the very first trunk at the base of the animal tree.

Traditional phylogenetic techniques have resolved about 95 percent of all evolutionary relationships, but an irksome five percent of cases remain unresolved, leading to controversies. To understand why certain relationships in the tree of life continue to be controversial, the authors of the new study took a look at pre-existing data sets, and compared the individual genes of jellies and sponges to finally come up with what they believe to be the world’s first animal.

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Read more: http://gizmodo.com/your-most-distant-living-relative-is-probably-this-tiny-1794206108

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Related: Contentious relationships in phylogenomic studies can be driven by a handful of genes (Nature Ecology & Evolution)

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Your Most Distant Animal Relative Is Probably This Tiny Jelly (Original Post) Eugene Apr 2017 OP
The jellyfish-vs-sponge feud continues... DetlefK Apr 2017 #1
Well, I know I probably have more in common with this jellyfish... ret5hd Apr 2017 #2
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