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John Postlethwait

Professor, Department of Biology
B.S., 1966, Purdue
Ph.D., 1970, Case Western Reserve

Research Interests

Genetic regulation of animal development including development of the nervous system, the mechanisms of sex determination, the origin of novel morphologies in evolution and the evolution of the vertebrate genome.

CV
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Lab Website

Stickleback at Oregon
Books in Print
Some Fun Runs

Vertebrates possess a variety of characters that distinguish them from their non-vertebrate chordate ancestors, including neural crest and epidermal placodes. What is the evolutionary genetic origin of the new molecular genetic functions that mold these novel morphologies? It has been suggested that gene duplication facilitates the evolution of developmental innovations, and vertebrates possess multiple copies of genes probably present in single copies in their chordate ancestors. We have discovered a genome duplication in zebrafish lineage and have collected evidence that suggests that this duplication event may be shared by all teleost fishes. Additional large scale gene or genome duplications preceded the divergence of human and zebrafish lineages.

We are investigating the possible roles of gene duplications in the origin of vertebrate innovations, working on the jawed fish zebrafish, the jawless fish lamprey, and a non-vertebrate chordate, the larvacean Oikopleura dioica. We aim to understand the developmental roles of genes related to those involved in making vertebrate developmental novelties by comparing their functions in the non-vertebrate chordate, zebrafish, and mammals.

Oikopleura has a characteristic chordate body plan, with a dorsal, hollow nerve cord, a notochord and pharyngeal gill slits. The fully grown adult has a head/trunk about 1 mm in length, and a posterior tail. Tissue on the head/trunk, termed the oikoplast, secretes a gelatinous 'house', which is an elaborate filter-feeding apparatus and provides buoyancy for this pelagic animal. At sexual maturity, the animal leaves the house and swims to the surface of the ocean, sheds eggs or sperm, and then dies. The life cycle is about 5 to 10 days, depending on temperature. (Photo courtesy of C. Cañestro.)

Trophic developmental ecomorphology for Kinder;
learning fun with Oikopleura dioica and stickleback.

Dr. Postlethwait with The Science Factory, Eugene OR, July 2007.

Journal Articles 2005-2008

Books in Print


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