An evolutionary tree, or phylogenetic tree, is a branching diagram that shows the evolutionary relationships between different biological species based on similarities and differences in their characteristics. Historically, this was done using their physical characteristics: the similarities and differences in the anatomy of different species.
However, advances in gene technology now allow biologists to use genetic data to decipher evolutionary relationships. According to a new study, scientists have found that molecular data lead to very different, sometimes dizzying, results from centuries of scientific work in classifying species by physical characteristics.
New research led by scientists at the Milner Center for Evolution at the University of Bath suggests that defining the evolutionary trees of organisms by comparing anatomy rather than genetic sequence is misleading. The study, published in the journal Communication Biology on May 31, 2022, shows that we often have to tear down centuries of academic work by classifying living things according to their form.
“This means that convergent evolution has deceived us, even the most intelligent 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 “genealogical trees” of animals by carefully examining the 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 gather the evolutionary relationships of species very quickly and economically, often proving that the organisms we once thought closely related to reality belong to a completely different set of tree branches.
For the first time, Bath scientists compared morphology-based phylogenetic trees with molecular-based ones and represented them by geographic location.
They found that animals grouped by molecular trees lived more geographically than animals grouped by morphological trees.
“It turns out many of our evolutionary trees are wrong,” said Matthew Wells, a professor of evolutionary paleobiology at the Milner Center for Evolution at the University of Bath.
“For more than a hundred years, we have categorized organisms according to their shape and grouped them anatomically, but molecular data often tell a slightly different story.
“Our study statistically shows that if an evolutionary animal tree is constructed from its molecular data, it is better suited to geographic distribution.
“The place where they live, their biogeography, is an important source of evolutionary evidence that was familiar to Darwin and his contemporaries.
“For example, shrews, pigskins, elephants, golden moles, and swimming manatees come from the same large branch of mammalian evolution, although they look very different from each other (and live in very different ways. ).
“The molecular trees brought them together in a group called Afrotheria, or as they say, because they all come from the African continent, so the group coincides with biogeography.”
Molecular phylogenetic trees show that elephant shrews are more closely related to elephants than to shrews. Credit: Danny Ye
The study found that convergent evolution, when a trait develops separately in two groups of non-genetically related organisms, is more common than biologists previously thought.
Professor Wells said: “We already have many famous examples of convergent evolution, such as flight evolving separately in birds, bats and insects, or complex camera eyes evolving separately in squid and humans.
“But now, with molecular data, we can see that convergent evolution is happening all the time; things that we thought were closely related are often found below the tree of life.
“People who make a living as imitators often don’t identify with the celebrities they represent, and people in a family are not always the same; so are evolutionary trees.
“This shows that evolution continues to reinvent things, proposing a similar solution every time the problem lies in a different branch of the evolution tree.
“This means that convergent evolution has deceived us, even the most intelligent evolutionary biologists and anatomists, for over 100 years!”
Jack Auston, co-author and first author of the article, said: “The idea that biogeography could reflect the history of evolution was a big part of what drove Darwin to develop his theory of evolution through of natural selection, so it’s pretty amazing that he did. ” t … in a simple way. Extremely.[{”Attribute=””>accuracyofthisevolutionarytreebeforenow[{”attribute=””>accuracyofevolutionarytreesinthiswaybeforenow[{”attribute=””>exactituddelsarbresevolutiusd’aquestamaneraabansd’ara[{”attribute=””>accuracyofevolutionarytreesinthiswaybeforenow
“What’s more exciting is that we find solid statistical evidence that molecular trees fit better not only into groups like Afrotheria, but also into the tree of life of birds, reptiles, insects and plants.
“Being such a widespread pattern makes it much more potentially useful as a general test of different evolutionary trees, but it also shows how widespread convergent evolution has been when it comes to deceiving us.”
Reference: “Molecular phylogenies map to biogeography better than morphological ones” by Jack W. Oyston, Mark Wilkinson, Marcello Ruta and Matthew A. Wills, May 31, 2022, Communications Biology.DOI: 10.1038 / s42003-022-03482-x