The insight and intuition developed over the past 50 years about how species form in terrestrial habitats does not apply often to speciation in the sea. Two new biological tools will be used in the study of marine speciation in order to understand biodiversity in the world's most diverse marine habitat: the Indo-West Pacific. Recent advances in biotechnology allow DNA segments from the nuclear and mitochondrial genomes of four species of tropical sea urchins to be sequenced. Previous results show that these species are the most closely related urchin species known, and new sequence data will show how genetic distinctions arise early in the divergence of new species. The data analysis will take advantage of recent techniques that emphasize the genealogical trees of DNA sequences. The parallel analysis of different types of DNA segments will provide a unique body of information explaining the evolutionary events surrounding speciation in the group. The results will be generalizable to other groups, and allow an understanding of how and why the large number of co- occurring species in the tropical oceans has arisen and is maintained.
