title: The Evolution of Haploid Chromosome Numbers in the Sunflower Family.
abstract: Chromosome number changes during the evolution of angiosperms are likely to have played a major role in speciation. Their study is of utmost importance, especially now, as a probabilistic model is available to study chromosome evolution within a phylogenetic framework. In the present study, likelihood models of chromosome number evolution were fitted to the largest family of flowering plants, the Asteraceae. Specifically, a phylogenetic supertree of this family was used to reconstruct the ancestral chromosome number and infer genomic events. Our approach inferred that the ancestral chromosome number of the family is n = 9. Also, according to the model that best explained our data, the evolution of haploid chromosome numbers in Asteraceae was a very dynamic process, with genome duplications and descending dysploidy being the most frequent genomic events in the evolution of this family. This model inferred more than one hundred whole genome duplication events; however, it did not find evidence for a paleopolyploidization at the base of this family, which has previously been hypothesized on the basis of sequence data from a limited number of species. The obtained results and potential causes of these discrepancies are discussed.
authors: Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Coimbra, Portugal luciemota.bio@gmail.com.
authors: Lucie
authors: L
authors: Mota
authors: Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Coimbra, Portugal.|Department of Functional and Evolutionary Ecology, Estación Experimental de Zonas Áridas (EEZA-CSIC), Almería, Spain.|Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
authors: Rubén
authors: R
authors: Torices
authors: Centre for Functional Ecology (CFE), Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
authors: João
authors: J
authors: Loureiro
mesh_terms: D032461:Chromosomes, Plant / Q000235:genetics*; D019143:Evolution, Molecular; D006238:Haploidy; D006368:Helianthus / Q000145:classification / Q000235:genetics*; D059785:Karyotype; D010802:Phylogeny
keywords: ancestral chromosome number; duplication; dysploidy; polyploidy; probabilistic models; sunflower family