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Dissection and Downstream Analysis of Zebra Finch Embryos at Early Stages of Development
Published on: June 21, 2014
Early penguin fossils, plus mitochondrial genomes, calibrate avian evolution
Kerryn E Slack1, Craig M Jones, Tatsuro Ando
1Allan Wilson Center for Molecular Ecology and Evolution, Institute of Molecular BioSciences, Massey University, Palmerston North, New Zealand.
Molecular Biology and Evolution
|March 15, 2006
Summary
Earliest penguin fossils and mitochondrial DNA reveal modern birds radiated in the Late Cretaceous, challenging macroevolutionary models. This study integrates paleontology and molecular biology to test evolutionary sufficiency.
Area of Science:
- Paleontology
- Molecular Biology
- Evolutionary Biology
Background:
- Testing macroevolutionary models requires interdisciplinary collaboration between molecular biologists and paleontologists.
- The Late Cretaceous period is crucial for understanding avian evolution and the diversification of modern bird lineages.
Purpose of the Study:
- To test the sufficiency of microevolutionary processes for macroevolution by examining events around the Late Cretaceous.
- To establish a reliable calibration point for avian evolution using early penguin fossils and molecular data.
Main Methods:
- Describing the earliest penguin fossils (new genus Waimanu) from New Zealand.
- Analyzing complete mitochondrial genomes from an albatross, petrel, and loon.
- Combining fossil calibration points with DNA sequences using maximum likelihood and Bayesian analysis.
Main Results:
- Earliest penguin fossils provide a divergence estimate of 61-62 Ma, calibrating avian evolution.
- Modern bird lineages (crown group) radiated in the Late Cretaceous, with sea and shorebirds diverging around 74 Ma.
- Pterosaurs showed decreased diversity and disappearance of smaller species before the Cretaceous-Tertiary boundary.
Conclusions:
- Modern birds coexisted with archaic birds and pterosaurs during the Late Cretaceous.
- The findings suggest a significant radiation of modern birds occurred earlier than previously thought.
- Further research on pterosaur life histories and more fossil/molecular data are needed to fully understand biotic interactions and test macroevolutionary sufficiency.
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