Genome duplication responsible for more plant species than previously thought.Byline: ANI Washington, August 13 (ANI): In a new research, a team of scientists has found that extra genomes appear, on average, to offer no benefit or disadvantage to plants, but still play a much more important role in the origin of new species than previously thought. The research was done by scientists from Indiana University Bloomington and three other institutions. Plant biologists have long suspected polyploidy Polyploidy The occurrence of related forms possessing chromosome numbers which are multiples of a basic number (n), the haploid number. Forms having 3n chromosomes are triploids; 4n, tetraploids; 5n, pentaploids, and so on. - the heritable her·i·ta·ble adj. 1. Capable of being passed from one generation to the next; hereditary. 2. Capable of inheriting or taking by inheritance. acquisition of extra chromosome sets - was a gateway to speciation speciation Formation of new and distinct species, whereby a single evolutionary line splits into two or more genetically independent ones. One of the fundamental processes of evolution, speciation may occur in many ways. . But, the consensus was that polyploidy is a minor force, a mere anomaly that accounts for 3 or 4 percent of the world's flowers and ferns. Now, the first direct, comprehensive survey of polyploid pol·y·ploid adj. Having extra sets of chromosomes. n. An organism with more than two sets of chromosomes. pol speciation in plant evolution severely challenges that notion. "In the present paper, we make it clear that it is a common process," said evolutionary biologist and lead author Troy Wood, who began the research during graduate training at IU Bloomington. "Fifteen percent of flowering plant species and almost a third of fern species are directly derived from polyploidy," he added. The scientists' exhaustive survey of published phylogenetic phy·lo·ge·net·ic adj. 1. Of or relating to phylogeny or phylogenetics. 2. Relating to or based on evolutionary development or history. and genomic data also shows that plant lineages starting with a polyploid ancestor appear to be no more successful at spawning species than diploid diploid /dip·loid/ (dip´loid) 1. having two sets of chromosomes, as normally found in the somatic cells; in humans, the diploid number is 46. 2. an individual or cell having two full sets of homologous chromosomes. plants, which have two sets of chromosomes. "The fact that polyploidy seems to have no effect on diversification rates should reduce the number of enthusiastic commentaries about the 'advantages of polyploidy'," said IU Bloomington evolutionary biologist and paper coauthor Loren Rieseberg, who supervised the research. "However, our diversification rate analyses only examined recent polyploids. A future area of research should be to ask whether more ancient polyploidy events have increased diversification rates," he added. (ANI) Copyright 2009 Asian News International The Asian News International (ANI) agency provides multimedia news to China and 50 bureaus in India. It covers virtually all of South Asia since its foundation and presently claims, on its official website, to be the leading South Asia-wide news agency. (ANI) - All Rights Reserved. Provided by Syndigate.info an Albawaba.com company |
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