The majesty of the Bald Eagle elevated this species to an important position for many Native American, First Nations, and some Meso-American cultures.  Bald Eagles are sacred and therefore their feathers are central to many religious and spiritual ceremonies and to honor noteworthy achievements and qualities.  Similarly, the founding fathers of the U.S. chose the bald eagle to be the national symbol of this country.

 

Despite their cultural importance, Bald Eagles faced a combination of direct persecution and environmental pollutants (organochlorides, heavy metals, pesticides, insecticides) that led to dramatic population declines in the continental U.S.  Although it is difficult to know exactly how many Bald Eagles existed prior to this decline, it has been estimated that within the continental U.S. at least 100,000 pairs of Bald Eagles existed during the mid-1800s.  However, by the 1970s, many local populations throughout the contiguous 48 states had either gone extinct of had declined to an estimated 487 nesting pairs mainly due to the use of DDT.  Bald Eagles are legally protected under the Bald and Golden Eagle Protection Act and the Migratory Bird Treaty Act and this protection, coupled with other conservation measures allowed Bald Eagles to escape the brink of extinction.  In fact, the Bald Eagle is used as a flagship and an umbrella species for conservation throughout North America.

 

After the population decline, many facilities worked to move bald eagles back into the areas they were extirpated. These translocations were done by removing the first clutch of eggs from a nest, bringing them into captivity, and hacking the young eagles out into the desired location. The eggs are collected early in the season so that the breeding pair will lay another clutch of eggs and careful consideration is taken for the eagles raised in captivity so that they will not become, imprinted, or acclimated to people. All of the translocations conducted in this manor did not take the natural genetic partitioning or the genetic effects of the bottleneck into consideration, thereby leaving many of today’s genetic questions unanswered.

 

Although the Bald Eagle appears to have escaped extinction, our knowledge of many aspects of Bald Eagle biology is so poor that it is difficult to develop scientifically based management plans for this ecologically and culturally important species.  Understanding the partitioning of genetic variation within and among populations of Bald Eagles is critical for their proper management as it allows for the delineation of conservation/management units necessary to minimize the loss of genetic diversity, preserve the existing genetic structure of the species, and determine natal origins of individuals.  Identification of conservation/management units is the first step is any conservation/management plan so that managers and policy makers understand the boundaries of the population units they are attempting to conserve.  Unfortunately, for Bald Eagles the existence of conservation/management unit boundaries are unknown, and in fact, have never been evaluated with genetic data. By determining the current genetic variation, wildlife managers can work to preserve the genetic variation thereby allowing the species the ability to adapt to future diseases and climate change.

 

The overarching objective of our study on Bald Eagles is to develop “DNA Zipcodes” so that we can determine biologically and genetically relevant units for the management of Bald Eagles.  Moreover, once these genetically defined units are determined, these DNA Zipcodes will allow us to genetically assign individuals to their natal origin.  To identify the DNA Zipcodes, we are utilizing Single Nucleotide Polymorphisms (SNPs).  To date, we have used low coverage genomic sequencing and RadTag sequencing of approximately 200 Bald Eagles from across the North America and identified approximately 1.5 million SNPs.  After aligning these data to a Bald Eagle genome, we identified SNPs that were in noncoding intergenic regions, those in coding regions, as well as those upstream or downstream of coding regions.  Finally, we reduced this approximately 1.5 million SNPs to about 50,000 SNPs with about half in intergenic regions and the other half either in ecologically relevant genes or upstream or downstream of these genes.  These ~50,000 SNPs are being placed on an array (SNP Chip) so that all future birds can be genotyped for the same loci.

 

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