Defining the ancestral eutherian karyotype: A cladistic interpretation of chromosome painting and genome sequence assembly data
Date
2008
Authors
Robinson T.J.
Ruiz-Herrera A.
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Abstract
A cladistic analysis of genome assemblies (syntenic associations) for eutherian mammals against two distant outgroup species-opossum and chicken-permitted a refinement of the 46-chromosome karyotype formerly inferred in the ancestral eutherian. We show that two intact chromosome pairs (corresponding to human chromosomes 13 and 18) and three conserved chromosome segments (10q, 19p and 8q in the human karyotype) are probably symplesiomorphic for Eutheria because they are also present as unaltered orthologues in one or both outgroups. Seven additional syntenies (4q/8p/4pq, 3p/21, 14/15, 10p/12pq/22qt, 19q/16q, 16p/7a and 12qt/22q), each involving human chromosomal segments that in various combinations correspond to complete chromosomes in the ancestral eutherian karyotype, are also present in one or both outgroup taxa and thus are probable symplesiomorphies for Eutheria. Interestingly, several of the symplesiomorphic characters identified in chicken and/or opossum are present in more distant outgroups such as pufferfish and zebrafish (for example 3p/21, 14/15, 19q/16q and 16p/7a), suggesting their retention since vertebrate common ancestry ∼450 million years ago. However, eight intact pairs (corresponding to human chromosomes 1, 5, 6, 9, 11, 17, 20 and the X) and three chromosome segments (7b, 2p-q13 and 2q13-qter) are derived characters potentially consistent with eutherian monophyly. Our analyses clarify the distinction between shared-ancestral and shared-derived homology in the eutherian ancestral karyotype. © 2008 Springer Science+Business Media B.V.
Description
Keywords
article, chicken, chromosome, chromosome 1, chromosome 10p, chromosome 10q, chromosome 11, chromosome 13, chromosome 14, chromosome 15, chromosome 16p, chromosome 16q, chromosome 17, chromosome 18, chromosome 19p, chromosome 19q, chromosome 20, chromosome 21, chromosome 22q, chromosome 2p, chromosome 3p, chromosome 4q, chromosome 5, chromosome 6, chromosome 8p, chromosome 8q, chromosome 9, chromosome painting, chromosome pairing, cladistics, gene sequence, human, karyotype, monophyly, nonhuman, opossum, priority journal, puffer fish, X chromosome, zebra fish, Animals, Chromosome Painting, Chromosomes, Mammalian, Evolution, Molecular, Karyotyping, Mammals, Phylogeny, Species Specificity, Synteny, Danio rerio, Didelphidae, Eutheria, Tetraodontidae, Vertebrata
Citation
Chromosome Research
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