The Molecular Basis of Species-Specific Craniofacial Patterning in Avians

Harvard University, Cambridge MA

Investigators

Abstract

The research proposed by Dr. Abzhanov crosses traditional research boundaries as it incorporates work on one of the iconographic evolutionary systems, Darwin's finches, with developmental and molecular techniques. Craniofacial features in vertebrates often display a number of adaptive species-specific characteristics. The classic example is the diversity in size and shape of the beaks of the Galapagos or "Darwin's" finches. Comparison of the expression patterns of various growth factors during craniofacial development in six species of "Darwin's" finches found that the level, extent and timing of expression of Bone morphogenetic protein 4 (Bmp4) correlated with beak morphology. In addition, when Bmp4 levels were experimentally altered in the chicken embryo the resulting morphologies mimicked that of Darwin's finches, suggesting an important role for Bmp4 in craniofacial diversity. As several aspects of Bmp4 regulation, structure and function may be important for craniofacial morphogenesis, Dr. Abzhanov proposes to examine the evolution of this important gene. Dr. Abzhanov's will focus his analyses on the genomic regulation of Bmp4 during craniofacial development in the chicken embryo and in two key species of Darwin's finches. Analysis of Bmp4 regulation is of great general interest not only to developmental and evolutionary biologists, but also to more specialized scientists such as bone scientists and craniofacial biologists. These studies have the potential to explain the relationship between adaptive morphological change and molecular changes at the level of gene regulation and link evolutionary processes with developmental mechanisms. A better understanding of evolution is critical to science education in the U.S.. Results of this study will be broadly disseminated by the PI, science writers and theoreticians who follow important developments in the field. Previous work on this project has already attracted attention from college textbook writers, high school teachers, and international science news magazines. This work will encourage the link between evolution and development in the minds of general scientific and public audience. Integration of this work with long-standing evolutionary, ecological and conservation studies on Darwin's finches will provide opportunity for interdisciplinary research interactions and training in developmental biology, evolution and field studies for graduate students and post-doctoral fellows from diverse backgrounds. Dr. Abzhanov regularly employs and trains students from Ecuador and 50% of these former field assistants are now pursuing their graduate careers in the U.S.. .