Term of Award

Spring 2014

Degree Name

Master of Science in Biology (M.S.)

Document Type and Release Option

Thesis (restricted to Georgia Southern)

Department

Department of Biology

Committee Chair

Lorne M. Wolfe

Committee Member 1

Lissa Legee

Committee Member 2

J. Scott Harrison

Abstract

Genetic engineering may be able to help address plant evolution questions by directly manipulating floral traits at the genetic level, in order to isolate individual traits and examine fitness associated with traits. Pleiotropy is a potentially confounding effect of this approach and must be addressed before genetic engineering may be used as an experimental approach to address experimental questions. This research looked at the pleiotropic effects of a single gene change in Ipomoea quamoclit, a red-flowering morning glory, that was genetically engineered to bloom blue.

Plants of the wild-type and the genetically engineered type were grown in Georgia Southern University’s greenhouse. Half the plants were grown in gallon size pots. The other half were grown in four inch square pots to induce stress, as stress can enhance pleiotropic effects. Several life history traits, floral characteristics, and fruit and seed traits were recorded. An outcrossing experiment was performed to examine differences in pollen and ova fitness between the color morphs.

The single genetic change to create blue-flowering I. quamoclit resulted in changes in almost every trait measured. Overall, red plants had much higher fitness than blue plants, regardless of pot size. The interaction of color and pot size did not affect most traits, but it did have a highly significant effect on nectar production and number of flowers produced. Blue plants’ reproductive fitness improved slightly when they were crossed with non-identical blues and especially with red plants, but their pollen and ova were inferior to red plants’ whether selfing or outcrossing.

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