How are birds related? A new study might provide some clues.
Where do birds come from? That? been a difficult question for scientists to answer but a new study might shed some light on the answer. Published in Nature, the study, “A comprehensive phylogeny of birds (Aves) using targeted next-generation DNA sequencing,?looked at the genomic sequence of 198 bird species that represented about 90 percent of all known birds. The results revealed some surprisingly new information.
First off, we have to explain why it? been so difficult to decipher where birds come from. As Phys.org writes in their article, “Group builds most comprehensive family tree of birds to date:?lt;/span>
“Building a family tree for modern birds has been difficult for scientists because of the dearth of fossil evidence going past 66 million years?he time before the mass extinction that wiped out the other dinosaurs. After the extinction, bird species evolved so rapidly that it has been difficult to use traditional genomic techniques to follow the paths of the evolution of new species, which in turn has made it almost impossible to create an accurate tree. To overcome such problems the researchers with this latest effort used a different type of genomic sequencing technique?t is called anchored hybrid enrichment and allows for sampling parts of the genome that evolved both slowly and more quickly in the flanking regions.?lt;/span>
What were the results? “The team found that virtually all birds (excluding flightless and some chickens and ducks) could be grouped into five sub-groups, i.e. major clads,?Phys.org wrote. “They also found evidence that suggested that all modern birds likely evolved from a single ancestor, one that lived approximately 75 million years ago, or ten million years before all the other dinosaurs went extinct?irds in general are believed to have evolved from the dinosaur family, developing feathers approximately 150 million years ago.?lt;/span>
According to Reuters, the new research also revealed that modern birds might have evolved from three surviving bird lineages after the mass extinction that killed the dinosaurs 66 million years ago. Researchers told Reuters in their article “Ruffling the feathers: scientists formulate bird family tree,?that most aquatic birds might have evolved from single common ancestor as “opposed to evolving an aquatic ecology multiple times independently,” Cornell University ornithologist Jacob Berv told Reuters.
Land birds, such as woodpeckers and chickadees, might have evolved from a meat-eating hawk-like ancestor, Yale University ornithologist Richard Prum explained to Reuters.
“Living birds have a very long and complex history. Any attempt to understand their biology at a broad scale requires an understanding of this deep historical context,” Berv told Reuters. “It’s critical to every area of bird biology. How they act, where they live, what they look like, how they communicate: it’s all linked to how they evolved in relation to each other.”
As the researchers write in their abstract:
“Although reconstruction of the phylogeny of living birds has progressed tremendously in the last decade, the evolutionary history of Neoaves? clade that encompasses nearly all living bird species?emains the greatest unresolved challenge in dinosaur systematics. Here we investigate avian phylogeny with an unprecedented scale of data: >390,000 bases of genomic sequence data from each of 198 species of living birds, representing all major avian lineages, and two crocodilian outgroups. Sequence data were collected using anchored hybrid enrichment, yielding 259 nuclear loci with an average length of 1,523 bases for a total data set of over 7.8 ?107 bases. Bayesian and maximum likelihood analyses yielded highly supported and nearly identical phylogenetic trees for all major avian lineages. Five major clades form successive sister groups to the rest of Neoaves: (1) a clade including nightjars, other caprimulgiforms, swifts, and hummingbirds; (2) a clade uniting cuckoos, bustards, and turacos with pigeons, mesites, and sandgrouse; (3) cranes and their relatives; (4) a comprehensive waterbird clade, including all diving, wading, and shorebirds; and (5) a comprehensive landbird clade with the enigmatic hoatzin (Opisthocomus hoazin) as the sister group to the rest. Neither of the two main, recently proposed Neoavian clades?olumbea and Passerea?ere supported as monophyletic. The results of our divergence time analyses are congruent with the palaeontological record, supporting a major radiation of crown birds in the wake of the Cretaceous?alaeogene (K?g) mass extinction.?lt;/span>