Most of our evolutionary trees are probably wrong

According to the molecular phylogenetic tree, elephant shrews are more closely related to elephants than to shrews.

A phylogenetic tree or phylogenetic tree is a clade diagram that shows the evolutionary relationships between different biological species based on similarities and differences in traits. Historically, this has been done using their physical characteristics – the anatomical similarities and differences between species.

However, advances in genetic technology now allow biologists to use genetic data to decipher evolutionary relationships. Scientists have found that molecular data can lead to dramatically different results, sometimes overturning centuries of scientific work to classify species based on physical characteristics, according to a new study.

Defining an organism’s evolutionary tree by comparing anatomical structures rather than genetic sequences is misleading, according to a new study led by scientists at the University of Bath’s Milner Centre for Evolution.The study was published in the journal Communication Biology On May 31, 2022, it shows that we often need to dismantle the academic work that has been classifying living things according to their shape for centuries.

“This means that convergent evolution has been deceiving us – even the brightest evolutionary biologists and anatomists – for over 100 years!” – Matthew Wells

Since Darwin and his contemporaries in the 19th century, biologists have attempted to reconstruct the “family tree” of animals by carefully examining differences in animal anatomy and structure (morphology).

However, with the development of rapid gene sequencing technology, biologists are now able to use genetic (molecular) data to help piece together the evolutionary relationships of species very quickly and cheaply, often proving that organisms we once thought were closely related belonged to a completely different group of reality twigs.

For the first time, scientists at Bath have compared morphology-based phylogenetic trees with molecular data-based phylogenetic trees and plotted them by geographic location.

They found that animals grouped by molecular trees lived geographically closer together than animals grouped using morphological trees.

“It turns out that many of our evolutionary trees are wrong,” said Matthew Wells, professor of evolutionary paleontology at the Milner Centre for Evolution at the University of Bath.

“For over a hundred years, we have classified organisms based on their shape and anatomical characteristics, but molecular data often tell a slightly different story.

“Our study demonstrates statistically that if you build an evolutionary tree from molecular data on animals, it’s generally better suited to their geographic distribution.

“Where things live—their biogeography—is an important source of evolutionary evidence familiar to Darwin and his contemporaries.

“For example, young shrews, pigskins, elephants, golden moles, and swimming manatees all descend from the same large branch of mammalian evolution — even though they are very different from each other (and live in completely different ways).

“The molecular tree clustered them in a group called Afrotheria, or so called because they were all from the African continent, so the group matched the biogeography.”

Evolution molecular elephant

The molecular phylogenetic tree showed that the elephant shrew is more closely related to the elephant than to the shrew.Credit: Danny Ye

The study found that convergent evolution — when a trait evolves separately in two groups of genetically unrelated organisms — is more common than biologists previously thought.

Professor Wells said: “We already have many famous examples of convergent evolution, such as flight in birds, bats and insects, or complex camera eyes in squid and humans.

“But now, with molecular data, we can see that convergent evolution is happening all the time – things that we think are closely related tend to be further down the tree of life.

“People who make a living as copycats often don’t identify with the famous people they represent, and people in a family aren’t always alike — neither does the evolutionary tree.

“It’s proof that evolution is constantly reinventing things, coming up with similar solutions each time it finds a problem on a different branch of the evolutionary tree.

“This means that convergent evolution has been deceiving us – even the brightest evolutionary biologists and anatomists – for over 100 years!”

“The idea that biogeography can reflect evolutionary history was an important part of what led Darwin to develop his theory of evolution through natural selection, so it’s surprising he didn’t,” said Jack Oston, research associate and first author of the paper. for a very simple method.[{” attribute=””>accuracy of evolutionary trees in this way before now.

“What’s most exciting is that we find strong statistical proof of molecular trees fitting better not just in groups like Afrotheria, but across the tree of life in birds, reptiles, insects, and plants too.

“It being such a widespread pattern makes it much more potentially useful as a general test of different evolutionary trees, but it also shows just how pervasive convergent evolution has been when it comes to misleading us.”

Reference: “Molecular phylogenies map to biogeography better than morphological ones” by Jack W. Oyston, Mark Wilkinson, Marcello Ruta and Matthew A. Wills, 31 May 2022, Communications Biology.
DOI: 10.1038/s42003-022-03482-x

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