Environmental and Comparative Genomics Research Projects
Bald Eagle

Bald eagle EST database (EagleESTbase)
In 1963 bald eagle (Haliaeetus leucocephalus) populations in the United States reached a record low at 417 breeding pairs (Federal Register, 1995). This was mainly due to environmental contamination by DDT and other pesticides, and habitat destruction. When the Endangered Species Act was introduced in 1973, the bald eagle was classified as an endangered species. Due to collective efforts of researchers, conservationists and government agencies, numbers of bald eagles in the US are on the rise and their status has been reclassified to "threatened" in the continental US. In Massachusetts (MA), the initial breeding population was very small (n = 9 pairs in 1998) and there is concern that future generations will inbreed. Little is known about levels of genetic diversity and organization of the bald eagle genome. To address this, RAPD technique was used to evaluate genetic diversity of an artificially restored nesting bald eagle population in MA. RAPD analysis using 41 individuals and 15 oligonucleotide primers showed 22% polymorphism. Because RAPD fingerprints from feather DNA were not comparable with those of blood DNA of the same animal, a ~307 bp DNA of mitochondrial cytochrome b gene was sequenced from both tissues. Similar sequences were obtained from blood and feather mtDNA of each bird indicating that feather samples could be used as an alternative, noninvasive source of DNA for genetic analysis. It is unknown if low genetic variation in MA eagles might effect susceptibility to emerging diseases. Information on population genetics may help to define the fitness of the bald eagle population. Future efforts should document potential impacts of environmental factors (e.g. pollutants) on disease susceptibility, reproduction, and genetic diversity. Blood mercury levels of MA bald eagles range from 60 to 780 ppb. Mercury and other heavy metals might cause harmful effects to the eagle genome as shown for the populations of many top predators which have plummeted. Using results from this project as a baseline, our efforts focus on developing highly polymorphic codominant markers like simple sequence repeats (SSRs) for use in population genetic studies, parentage testing, and mapping of the eagle genome. SSRs are being isolated from genomic libraries and expressed sequence tags obtained from bald eagles with high and low levels of mercury. Information obtained will help wildlife managers assess long-term survivability of our national symbol as well as adding polymorphic markers to the bald eagle genetic map and comparative genomics.

Alcivar-Warren, A., C. Bell, C. Mark, A. Dhar, D. Davis and M. Pokras. 2003. Bald eagle genomics. Book of Abstracts. Plant and Animal Genome XI, January 11-15, Town & Country Hotel, San Diego. Abstr. P678, p. 244. (View Abstract)

Related Publications

• RAPD genetic diversity: Mark, C, A.Dhar, D.Davis, M.Pokras and A. Alcivar-Warren. 2003. Low levels of genetic diversity in the threatened bald eagle (Haliaeetus leucocephalus) population from Massachusetts. Book of Abstracts. American Genetic Association, Conservation Genetics Conference, September 14-17, 2003, Front Royal, VA, abstr. p 48.
• Microsatellite genetic markers: Courchesne, S., Meola, D., Alcivar-Warren, A. 2005. Bald eagle (Haliaeetus leucocephalus) feathers as an alternative to blood for microsatellite DNA analysis: toward a non-invasive technique for conservation genetics. Foundations 23 (1):31-39.