Origin and Diversification of Peperomia (Piperaceae) in Madagascar
James F. Smith
Evolution has produced great biological diversity across the globe. Understanding how species got to be how they are now has been an important question for biologists going back to Darwin. As Darwin found back in the early 19th century, islands are particularly puzzling in regards to the diversity of species. Islands like Hawaii and the Galápagos’ have a long history of evolutionary studies because of their isolation. Other, larger islands, that are close to continents, like Madagascar, pose different questions, because their size and proximity to continents allow different evolutions to occur. One group of organisms to study on Madagascar is the herbaceous plant genus Peperomia that comprises over 1,500 species distributed throughout the tropics world-wide. Because of the distribution and species diversity of Peperomia, the hypothesis of the origin of this species in Madagascar can be tested through phylogenetic analysis, the study of evolutionary relationships. Data for the analysis are DNA sequences. To get the sequences, DNA of Malagasy samples has been extracted, purified and amplified. The DNA is then being compared to DNA sequences of other Peperomia species from throughout the tropics. As of this point in time, the data from one chloroplast gene shows multiple introductions from Africa, the South Pacific and potentially the New World, along with radiation of the species within Madagascar.
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