Darwin's 'Abominable Mystery' Haunts New Plant Tree of Life
A picture shows the newly made flowering plant tree of life, which allows scientists to understand how different species are related to each other.
A newly developed “plant tree of life” may help scientists crack an “abominable mystery” declared by Charles Darwin.
Flowering plants first evolved over 140 million years ago. Their sudden emergence across the world’s ecosystems confused the famed geologist, who wrote: “The rapid development, as far as we can judge, of all the higher plants within recent geological times is an abominable mystery.”
Researchers have now created a DNA tree of life, showing how different plant species are related to each other, by comparing the DNA sequences of over 9,500 flowering plants. Details of the chart, made by scientists from the Royal Botanic Gardens, Kew, in the U.K. and the Kunming Institute of Botany (KIB) of the Chinese Academy of Sciences, have been published in a Nature study.
The researchers used 200 fossils to trace how flowering plants evolved, and discovered that the first ones fed into 80 percent of those that still exist today. This development slowed somewhat for the next 100 million years, the study authors noted, until it picked up again 40 million years ago. This occurred around the same time that global temperatures dropped.
The authors believe their findings would have fascinated Darwin as it poses an answer to his abominable mystery. The findings also help modern-day scientists understand why species change and evolve in this way, the study reported.
Comparing DNA sequences that gathered over time—similar to a fossil record—allowed scientists to sequence various types of plant matter regardless of its age or how the DNA was degrading. This means that the vast collections of dried plant specimens, housed in the world’s herbarium collections, will be able to undergo genetic analysis.
One such specimen included a sandwort gathered around 200 years ago in Nepal. The specimen’s DNA quality was poor, however the researchers were able to position it within the tree.
They also discovered plants that have long been extinct, such as the Guadalupe Island olive (Hesperelaea palmeri) that disappeared in 1875. Among the 9,506 species sequenced in the study, 511 are currently threatened with extinction. This includes three that are already extinct.
Over 800 plants had their DNA sequenced for the very first time in the study, meaning the researchers were able to fill in important evolutionary gaps.
Scientists are hopeful of the potential the tree of life has for biodiversity research. Each plant’s location on the tree of life allows scientists to study its properties, similar to how an element can be studied by its position on the periodic table, the study authors wrote.
Because of this, scientists will find it “invaluable in improving many areas of science and beyond,” according to a summary of the findings.
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