Most of our evolutionary trees may be wrong

For the first time, scientists in Bath have compared phylogenetic trees based on morphology with those based on molecular data, plotting them by geographic location.

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

“It turns out that a lot of our evolutionary trees are wrong,” said Matthew Wells, professor of evolutionary paleobiology at the University of Bath’s Milner Center for Evolution.

“For more than a hundred years, we have been classifying organisms based on their anatomical shape and grouping, but molecular data often tell a slightly different story.

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

“The place where things live – their biogeography – is an important source of evolutionary evidence known to Darwin and his contemporaries.

“Little shrews, pig skins, elephants, golden moles, and swimming manatees, for example, all come from the same major branch of mammalian evolution—even though they look very different (and live in completely different ways).

“The Molecular Trees put them together in a group called Afrotheria, or so-called because they are all from the African continent, so the group corresponds to biogeography.”

The study found that convergent evolution — when a trait develops separately in two groups of organisms that are not genetically related — is more common than biologists previously thought.

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

“But now with the molecular data, we can see that convergent evolution is happening all the time — things that we thought were closely related are often very far apart on the tree of life.

“People who make a living as impersonators don’t usually have a relationship with celebrities impersonating them, and people within a family aren’t always the same — it’s the same with evolutionary trees, too.

“It proves that evolution keeps reinventing things and coming up with a similar solution every time a problem appears on a different branch of the evolution tree.

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

Dr. Jack Auston, co-author and lead author of the paper said: “The idea that biogeography can reflect evolutionary history was a big part of what prompted Darwin to develop his theory of evolution through natural selection, so it’s pretty surprising that she didn’t. It was seen as 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