Léolène Jean

Léolène Jean

University of New Hampshire

Biology


2005

Mentor: Dr. W. Kelley Thomas, Department of Biochemistry

Molecular diversity and functional analysis of the opsin genes expressed in Daphnia

Daphnia are branchiopod crustaceans that have been the subject of nearly three centuries of study by taxonomists, physiologists and limnologists. Probably more is known about how Daphnia interact with their environment than any other organism. Light in the environment of Daphnia and their visual ability may serve important functions in the detection of mates, predators and in regulating their migration. However, relatively little is known about the visual characteristics inDaphnia, especially the cell and molecular biology of their vision. The focus of my project is to find and characterize the genes for opsin proteins, which are light-sensitive pigments in Daphnia. These genes will be an important indication of Daphnia's ability to visualize light in its environment.

A complete sequence of the Daphnia genome is eminent. The Daphnia genome database will be searched using the DNA sequences homologous to the opsin genes of related organisms, such as the Fruit fly Drosophila melanogaster. Using standard methods, gene sequences will be compared to identify the opsin gene types found in Daphnia. Also the spectral sensitivity of the eye of Daphnia will be measured.

Daphnia were chosen as model organisms because they play a central role in freshwater ecology. They are primary feeders of algae and primary forage of fish and other interrelated organisms. Since the number or type of the light-sensitive pigments in an organism's eye determines the wavelengths of light that an organism can see, knowing what opsin genes Daphnia have will make it possible to predict what the organism can see in its environment. In addition, the knowledge developed will be critical to understanding how the environment interacts with genes in the process of an organism's adaptation to environmental change.

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