title: Phylogenetic history of paralogous gene quartets on human chromosomes 1, 2, 8 and 20 provides no evidence in favor of the vertebrate octoploidy hypothesis.
abstract: Fourfold paralogy regions in the human genome have been considered historical remnants of whole-genome duplication events predicted to have occurred early in vertebrate evolution. Taking advantage of the well-annotated and high-quality human genomic sequence map as well as the ever-increasing accessibility of large-scale genomic sequence data from a diverse range of animal species, we investigated the prediction that the ancestral vertebrate genome was shaped by two rapid rounds of whole-genome duplication within a period of 10 million years. Both the map self-comparison approach and a phylogenetic analysis revealed that gene families identified as tetralogous on human chromosomes 1/2/8/20 arose by small-scale duplication events that occurred at widely different time points in animal evolution. Furthermore, the data discount the likelihood that tree topologies of the form ((A,B)(C,D)) are best explained by the octoploidy hypothesis. We instead propose that such symmetrical tree patterns are also consistent with local duplications and rearrangement events.
authors.affiliation: National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan. abbasiam@qau.edu.pk
authors.forename: Amir Ali
authors.initials: AA
authors.lastname: Abbasi
authors.forename: Hafsa
authors.initials: H
authors.lastname: Hanif
mesh_terms: D002878:Chromosomes, Human, Pair 1 / Q000235:genetics*; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics*; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics*; D002898:Chromosomes, Human, Pair 8 / Q000235:genetics*; D019143:Evolution, Molecular; D020440:Gene Duplication; D006801:Humans; D008957:Models, Genetic; D010802:Phylogeny; D011003:Ploidies; D017422:Sequence Analysis, DNA