Hybrid Duck Study: What Is a Backcross Hybrid?

Backcross hybrids are progeny derived from an F1 hybrid mating with a member of one of its parental species. At each genetic locus F1 hybrids carry an allele from their mother species and an allele from their father species. Thus, for all genes that show fixed differences between the parental species, F1 hybrids will carry one gene from each parental species.

Note that the rarity of F1 hybrid waterfowl means that F1 hybrids will not find other F1s as mates; instead, they will mate with one of the parental species, forming F2 backcross progeny. Three quarters of the genes in F2 backcross hybrids come from their backcross parental, and ¼ genes from the other parent that produced their F1 mother or father. Backcross hybrids are important because they transfer genes laterally between the parental species. When F1 hybrids mate with only one of the parental species, then gene transfer is unidirectional, increasing genetic diversity only in the backcross parental.

If you have taken a hybrid that we can include in this study, please contact me (rohwer@uw.edu) or Burke Collections Manager, Chris Wood (puffinus@uw.edu; cell 253-740-1071) directly, and not through this forum. Chris will arrange shipping and can provide tissue vials for hybrids that are going to mounts. Also, please check out the Burke Ornithology homepage for more information on the Museum's collection of birds from around the world.

What We Need from the Hunting Community

Ideally, we would like to receive whole birds that will be preserved as scientific specimens, always available to researchers, students, and artists at the University of Washington Burke Museum. For each of these hybrids we would save a study skin, a fully extended wing, and a tissue sample. Genetic analysis will tell us the mother and father species for first generation hybrids (crosses between pure parental), and allow us to assess whether the hybrid is a first generation hybrid or a backcross between a first generation hybrid and one of the parental species. The study skin and the extended wing will allow us to describe the plumage of first and later generation hybrids in detail, hopefully leading to an illustrated guide to first and later generation hybrids. Artists will need these specimens to make proper illustrations!

We understand that some hunters will not give up a hybrid they want mounted. Although skin and wing specimens are far more valuable to the scientific community, good photos and a tissue sample, taken when the bird is being mounted, may allow us to include it in the study of hybrid origins. But whole birds offer much more. They can be used to describe plumages of different hybrid generations. They should help find genes coding for plumage differences in the parental species. And, we hope they will help understand why some hybrids are not simple "blends" of the parental species, instead showing characters not seen in either parental species.