Pacific Biosciences Research Center makes progress in understanding patterns of animal evolution

University of Hawaiʻi at Mānoa
Posted: Apr 8, 2008

HONOLULU - An international team of scientists led by researchers at the Kewalo Marine Lab of the Pacific Biosciences Research Center (PBRC) at the University of Hawaiʻi at Mānoa has made significant new progress on understanding the patterns of animal evolution, as reported in the April 10 journal of NATURE.

Over a four-year span, a team of experts in molecular and developmental biology, animal systematics, evolutionary biology, and computer science from the PBRC, Harvard, Scripps Institute of Oceanography, Zoological Museum of Copenhagen in Denmark, Kristineberg Marine Lab in Sweden, and the Natural History Museum in London, collected data from a wide array of animal diversity, doubling the number of different animal groups ever sampled. Many of the animals were collected along the shore and by SCUBA in local Hawaiian waters, while other rare samples were collected at marine labs around the world from Australia to Sweden.

The team collected the most commonly expressed genes from each species and compared them using complex computer bioinformatic and phylogenetic programs at several computer centers, including the PBRC Bioinformatics facility, to determine which species were more closely related to one another. "The analysis of these data were computationally intensive, requiring banks of dozens of computers running in parallel simultaneously over months of time to complete a single run," said Mark Martindale, professor and director of the Kewalo Marine Lab. The results showed strong support for many well agreed upon nodes, but also showed many new relationships that had never been proposed.

"These results show that morphological complexity is not correlated in simple ways with molecular complexity, that many developmental and morphological patterns were lost or secondarily simplified in some lineages, and that some features such as body segmentation and musculature evolved multiple times throughout evolutionary time," said Martindale. "The job is not complete, however, as some of the more obscure animals still need to be examined before they can be placed with certainty, but the approach the Kewalo team has perfected shows that the answer to reconstructing the relationship of all living animals is now within reach."

Life evolved in the sea and the world‘s oceans still house the greatest diversity of animal forms. Despite centuries of speculation, it is still not known how all the different kinds of animals are related to one another. This understanding will provide a framework for the direction of evolutionary change, when and how many times different developmental and morphological traits evolved, and to reconstruct the morphological complexity of animals at different times in history of life on Earth.

Scientists generally recognize 30-35 different "kinds" of animals, called "phyla," that are all related to one another by common descent. Arthropoda, is one phylum of animal that includes many different species including all insects (e.g. flies, bees, butterflies, moths, beetles) and crustaceans (e.g. shrimps, lobsters, crabs). Vertebrates (e.g. fish amphibians, reptiles birds, and mammals) are one other larger phylum of animal, leaving 28-33 other under studied animal phyla to account for.

Martindale adds, "Many of these animals are quite small and live between sand grains, but likely evolved well before the larger charismatic megafauna, such as whales, sharks, turtles and ahi that we see with our naked eyes on a day to day basis. "In order to gain an appreciation for the larger and more species groups, it is important to understand the evolutionary origin and relationship of all animal groups."

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