Our analyses recognize as an old genus (crown age 31Ma) whose evolutionary history has been profoundly affected by allopolyploidy.Between 16 and 21 allopolyploidizations are necessary to explain the diversification of the 16 major lineages (sections) of , suggesting that allopolyploidy has accounted for a high percentage—between 67% and 88%—of the speciation events at this level. In animals there have been two polyploidizations early in the vertebrate lineage (Dehal and Boore 2005), and there are nearly 200 examples of polyploidy in insects and vertebrates (Otto 2007) and many more in other invertebrate groups (Gregory and Mable 2005).Importantly, the coalescent-based method used herein circumvents the assumption of tree-like evolution required by most techniques for dating speciation events.This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited.Reconstructing the "correct" network for a set of polyploids depends on recovering all homoeologs, i.e., all subgenomes, in these polyploids.Assuming the presence of Viola subgenome lineages that were not detected by the nuclear gene phylogenies ("ghost subgenome lineages") significantly reduced the number of inferred polyploidization events.
“Sepanjang tempoh itu juga banyak berita baik dan positif mengenai Malaysia yang telah dipaparkan di halaman surat khabar dan majalah, baik tempatan mahupun luar negara,” katanya.This includes the return of many genes to single copy, disomic chromosomal inheritance, and often reduced genome size and chromosome numbers.Thus, the deeper the phylogeny, the more obscure the identification of polyploidy events and the greater the requirement for evidence from numerous genes.The theoretical and methodological approaches presented here for (i) constructing networks and (ii) dating speciation events within a network, have general applicability for phylogenetic studies of groups where allopolyploidization has occurred. Polyploidy is often classified based on the relatedness of the duplicated genomes, where autopolyploidy implies that the duplicated genomes are identical (homologuous) or nearly so and stem from the same species, and allopolyploidy refers to conditions where the duplicated genomes are nonidentical (homoeologous) and have been brought together within a single organism by interspecific hybridization.They make explicit use of a hitherto underexplored source of ploidy information from chromosome counts to help resolve phylogenetic cases where incomplete sequence data hampers network inference. Genome duplication is generally irreversible in the short term, and evidence of polyploidy may remain in the genome for hundreds of millions of years. Young polyploids (neopolyploids) are as a rule identifiable by increased genome size, doubled chromosome numbers, and redundant gene content compared with their progenitors.