Meet Irby Lovette
BY MIYOKO CHU
Lab's new director of Evolutionary Biology
 

Irby Lovette Photo by Tim Gallagher

For Irby Lovette, bird DNA provides a fascinating and intricate record of the fundamental causes and patterns of diversity in birds. Irby, the Lab's new director of Evolutionary Biology, is using genetic data to offer fresh insights on topics such as the diversification of warblers, geographic correlates of bird diversity, and speciation on islands.

Irby comes to the Lab from the Center for Tropical Research at San Francisco State University. He earned his Ph.D. in 1999 at the University of Pennsylvania, where he studied historical patterns and evolutionary processes in bird diversification. He will equip the Lab to answer questions about the evolutionary history, conservation, and behavior of birds using molecular methods in a new genetics laboratory, scheduled for completion in 2003.

With information gleaned from the DNA sequences of wood warblers, Irby is helping to reconstruct the history of speciation in this diverse family. His work on the 27 warblers in the genus Dendroica showed large genetic distances between species, indicating their ancient origins. By assuming that mutations in DNA accumulate in clocklike fashion, he calculated that an initial burst of speciation occurred 4.5-7 million years ago. If so, Dendroica wood-warbler species may have arisen in isolation from one another in the fragmented forests of that time. Only later did their breeding ranges overlap, as they do in the current landscape.

Irby is investigating broad patterns of genetic diversity to help explain why birds are more diverse in the tropics than in the temperate zone. He is also using genetic information to reveal patterns of colonization and speciation on islands. He has studied the diversification of honeycreepers and thrushes on the Hawaiian Islands and birds in the Caribbean, documenting the genetic uniqueness of species such as the endangered Montserrat Oriole.

In the genetics lab here at Sapsucker Woods, researchers will be able to use DNA samples to distinguish males and females in species where the sexes look alike, document the spread of avian disease strains, determine the identities of a nestling's parents, assess bird dispersal between forest fragments, and identify genetically distinct populations.

"We're not even close to finished with the important job of discovering and describing the evolutionary diversity of birds, functionally the cornerstone of all efforts to conserve biodiversity," Irby says.