Assessing genetic variation in natal populations of small Canada geese via microsatellite loci

Traditionally, waterfowl biologists have identified specific groups of Canada geese (Branta canadensis) by the recovery of marked individuals and/or their winter distribution. From winter distributions and field observations of marked birds, small Canada geese in the Central Flyway have been placed into two categories, the Tall Grass Prairie (TGP) and Short Grass Prairie (SGP) populations. These populations nest primarily in the Northwest Territories, Canada. The SGP nest between the Mackenzie River Delta and the Queen Maud Gulf along the Arctic Ocean, whereas the TGP geese nest from eastern Queen Maud Gulf to Baffin and Southampton Islands, and along the west coast of Hudson Bay. The SGP population winters in western Oklahoma, northeastem New Mexico, southeastern Colorado, with the largest portion residing in the panhandle of Texas. The TGP population winters in southeastern Oklahoma, and along the Gulf coast of Texas and Mexico.

Although banding and collaring data provide information on the organisms movement, it does not predict potential gene flow, nor does it give the history of a birds genetic make-up. We now have the technology to assess an organism's genetic background. Because Canada geese are philopatric, this behavior increases the potential for populations to become genetically isolated. This project sought to determine whether the genetic structure of individuals corresponds to the TGP and SGP categories defined by field observations. I tried to determine if there were genetic subdivisions among geographically distinct groups.

I conducted a search for genetic markers that provide direct rather than implied information regarding breeding groups. This was done by constructing a genomic DNA library and three microsatellite sub-libraries. Polymerase chain reaction (PCR) primers were constructed to amplify each microsatellite locus. For each of the five informative microsatellite loci, 13 natal populations (n = 458) of small Canada geese were assessed for allelic variation.