A grant has been awarded to Drs. Scott Edwards and Peter Beerli at the University of Washington to apply molecular genetic tools to study the evolution of Australian birds. Specifically, the project will use genetic data to make inferences about (1) when in geological time a series of avian species diverged across an important ecological barrier in northern Australia, the Carpentarian barrier; (2) the size of the populations of the ancestral species from which this series of present-day bird species in Australia arose; and (3) the magnitude of genetic differences between populations of songbirds distributed across this barrier. The research will use DNA sequence variation in a class of molecular genetic markers known as single-nucleotide polymorphisms (SNPs) at many different places in the genomes of these birds, as well as novel statistical methods, to make these inferences.
This project is significant because it will help clarify the timing and places of diversification of birds on an isolated continent (Australia), and thereby will facilitate comparisons with diversification of birds and other animals on other continents. This project will distinguish between two competing theories for the origin of current-day animal species, one of which says that much of this divergence took place very recently, less than 2 million years ago, the other of which, says that these divergence events probably took place much earlier. The results will help document global patterns of biological diversification, relate these patterns to environmental change, and thereby provide an historical context for conserving and even predicting evolutionary history. In addition, the data will provide measures of the amount of genetic variation within Australian bird species, thereby providing a gauge by which the genetic variability found in other species, including humans, can be compared.
