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Archive - Apr 13, 2011

Tiger-Parrots Occupy Own Perch on Evolutionary Tree

Researchers have found that the tiger-parrots of New Guinea‘s rainforests – named for their striped or barred plumage – are not, as has been widely accepted, closely related either to a group of rosella-like parrots found in Australia and Oceania, nor a similar group found in Asia and Africa. In press in Molecular Phylogenetics and Evolution, the scientists report that tiger-parrots instead occupy their own perch on the parrot evolutionary tree. Co-author, the Director of CSIRO’s Australian National Wildlife Collection (ANWC) Dr. Leo Joseph, said the findings will help improve our understanding of how parrots have evolved. “This research on tiger-parrots – and some other enigmatic Australian parrots such as the little-known Night Parrot of inland Australian deserts – sheds light on the bigger picture of parrot evolution for Australia and New Guinea,” Dr. Joseph said. “It has shown for the first time, for example, that tiger-parrots represent a very early branch of the parrot evolutionary tree in Australia and New Guinea. “The research team’s quest has been to understand the true places of parrots such as the Night Parrot and the tiger-parrots in the ecological and evolutionary history of parrots across the Australian continent. “During our research on these oddball parrots of Australia and New Guinea, we affirmed that the Australian parrots are far from one cohesive group. They appear, instead, to be made up of about five different main branches of the parrot evolutionary tree,” Dr Joseph said. “We have shown that the New Guinea tiger-parrots aren’t rosella-like parrots and that their resemblance in some aspects of their appearance to rosellas probably indicates some plumage characters that have been part of the evolution of parrots of Australia and New Guinea for a long time.

Circadian Rhythms Play Key Role in Plant Adaptation to Cold

Just as monarch butterflies depend on circadian cues to begin their annual migration, so do plants to survive freezing temperatures. All living things – humans, animals, plants, microbes – are influenced by circadian rhythms, which are physical, mental and behavioral changes that follow a 24-hour cycle. In the April 6, 2011 online edition of PNAS, Dr. Michael Thomashow, University Distinguished Professor of molecular genetics, along with MSU colleagues Dr. Malia Dong and Dr. Eva Farré, has identified that the circadian clock provides key input required for plants to attain maximum freezing tolerance. “The integration of cold-signaling pathways with the circadian clock may have been an important evolutionary event that has contributed to plant adaptation to cold environments,” Dr. Thomashow said. Dr. Thomashow, who is an elected member of the National Academy of Sciences for his contributions to the field of plant biology, has focused his research on the identification of stress response pathways involved in freezing and drought tolerance. Stresses, including extreme temperatures and water deficit, are major factors that limit the geographical locations where food and potential bioenergy crops can be grown. His research led to the identification of the C-repeat binding factor, or CBF response pathway, a stress pathway that can be found in many different plants and plays a major role in freezing and drought tolerance. Reducing abiotic stresses, such as extremes in temperature and drought, can help expand where crops can be grown and increase yields on an annual basis, Dr. Thomashow said.