Most of Our Evolutionary Trees Could Be Wrong

Elephant Shrew

Elephant shrews are more closely related to elephants than they are to shrews, according to molecular evolutionary trees.

An evolutionary tree, or phylogenetic tree, is a branching diagram showing the evolutionary relationships among various biological species based upon similarities and differences in their characteristics. Historically, this was done using their physical characteristics — the similarities and differences in various species’ anatomies.

However, advances in genetic technology now enable biologists to use genetic data to decipher evolutionary relationships. According to a new study, scientists are finding that the molecular data is leading to much different results, sometimes overturning centuries of scientific work in classifying species by physical traits.

New research led by scientists at the Milner Center for Evolution at the University of Bath suggests that determining evolutionary trees of organisms by comparing anatomy rather than gene sequences is misleading. The study, published in the journal Communications Biology on May 31, 2022, shows that we often need to overturn centuries of scholarly work that classified living things according to how they look.

“It means that convergent evolution has been fooling us — even the cleverest evolutionary biologists and anatomists — for over 100 years!” — Matthew Wills

Since Darwin and his contemporaries in the 19th Century, biologists have been trying to reconstruct the “family trees” of animals by carefully examining differences in their anatomy and structure (morphology).

However, with the development of rapid genetic sequencing techniques, biologists are now able to use genetic (molecular) data to help piece together evolutionary relationships for species very quickly and cheaply, often proving that organisms we once thought were closely related actually belong in completely different branches of the tree.

For the first time, scientists at Bath compared evolutionary trees based on morphology with those based on molecular data, and mapped them according to geographical location.

They found that the animals grouped together by molecular trees lived more closely together geographically than the animals grouped using the morphological trees.

Matthew Wills, Professor of Evolutionary Paleobiology at the Milner Center for Evolution at the University of Bath, said: “It turns out that we’ve got lots of our evolutionary trees wrong.

“For over a hundred years, we’ve been classifying organisms according to how they look and are put together anatomically, but molecular data often tells us a rather different story.

“Our study proves statistically that if you build an evolutionary tree of animals based on their molecular data, it often fits much better with their geographical distribution.

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

“For example, tiny elephant shrews, aardvarks, elephants, golden moles, and swimming manatees have all come from the same big branch of mammal evolution — despite the fact that they look completely different from one another (and live in…

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