How does polyploidy affect the evolutionary genetics of plants

How does polyploidy affect the evolutionary genetics of plants?

James F. Hancock

Professor, Horticulture

Physiological and Evolutionary Genetics of Plants

We are interested in the influence of polyploidy on the evolution of plant species. Of particular concern are the effects of autopolyploidy and allopolyploidy on genetic variability and genetic load. Only a few direct comparisons have been made of heterozygosity and self-fertility in related species of diploids, alloploids and autoploids.

Other studies focus on the factors regulating reproductive effort in perennial plant species. We have found that the degree of self-fertility plays an important role, but there are also large differences in gas exchange rates that influence allocation patterns. For example, photosynthetic optima range from 18°C to 30°C in blueberries, and net rates of CO2 assimilation vary by as much as 50 percent in strawberries. Reproductive outputs reveal corresponding variability.

We are also actively measuring gene flow between cultivated and wild cucurbits using native and engineered genes. Such studies have become increasingly important as biotechnologists prepare to release transgenic plants into the environment.

Selected Publications

Schumann, C.A. and J.F. Hancock. 1989. Paternal inheritance of plastids in Medicago sativa. Theor. Appl. Genet. 78:863-866.

Hancock, J.F., J.A. Flore and G.J. Galletta. 1989. Gas exchange properties of Fragaria x ananassa, F. chiloensis and their hybrids. Scientia. Hortic. 40:139-144.

Krebs, S.L. and J.F. Hancock. 1991. Embryonic genetic load in the highbush blueberry, Vaccinium corymbosum (Ericaceae). Amer. J. Bot. 78:1427-1437.

Hancock, J.F. and J.J. Luby. 1993. Genetic resources at our doorstep: The wild strawberries. Bio. Science 43:141-149.

Hokanson, K.E. and J.F. Hancock. 1993. The lowbush blueberry Vaccinium angustifolium Aiton may be an autotetroploid. Can. J. Bot. 73:889-891.

Hokanson, S.C., J.G. Isebrands, R.J. Jensen and J.F. Hancock. 1993. Isozyme variation in oaks of the Apostle Islands in Wisconsin: Genetic structure and levels of inbreeding in Quercus rubra and Quercus ellipsoidalis. Amer. J. Bot. 80:1349-1357.