The updated family tree, detailed in two complementary papers published today in the journal Nature and the Proceedings of the National Academy of Sciences, reveals patterns in the evolutionary history of birds following the cataclysmic mass extinction event that wiped out the dinosaurs 66 million years ago. The authors observed sharp increases in effective population size, substitution rates and relative brain size in early birds, shedding new light on the adaptive mechanisms that drove avian diversification in the aftermath of this pivotal event. The researchers also closely examined one of the branches of the new family tree and found that flamingos and doves are more distantly related than previous genome-wide analyses had shown.
“Our goal is to reconstruct the entire evolutionary history of all birds,” said Professor Siavash Mirarab, a researcher at the University of California, San Diego.
The work is part of the Bird 10,000 Genomes (B10K) Project, a multi-institutional effort led by the University of Copenhagen, Zhejiang University and the University of California, San Diego that aims to generate draft genome sequences for about 10,500 extant bird species.
At the heart of these studies lies a suite of algorithms known as ASTRAL, which Professor Mirarab and colleagues developed to infer evolutionary relationships with unprecedented scalability, accuracy and speed.
By harnessing the power of these algorithms, they integrated genomic data from over 60,000 genomic regions, providing a robust statistical foundation for their analyses.
The researchers then examined the evolutionary history of individual segments across the genome.
From there, they pieced together a mosaic of gene trees, which were then compiled into a comprehensive species tree.
This meticulous approach enabled the researchers to construct a new and improved bird family tree that delineates complex branching events with remarkable precision and detail, even in cases of historical…
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