학술논문

Genome evolution in the allotetraploid frog Xenopus laevis
Document Type
article
Source
Nature. 538(7625)
Subject
Biological Sciences
Bioinformatics and Computational Biology
Genetics
Biotechnology
Human Genome
Animals
Chromosomes
Conserved Sequence
DNA Transposable Elements
Diploidy
Evolution
Molecular
Female
Gene Deletion
Gene Expression Profiling
Genome
Karyotype
Molecular Sequence Annotation
Mutagenesis
Phylogeny
Pseudogenes
Tetraploidy
Xenopus
Xenopus laevis
General Science & Technology
Language
Abstract
To explore the origins and consequences of tetraploidy in the African clawed frog, we sequenced the Xenopus laevis genome and compared it to the related diploid X. tropicalis genome. We characterize the allotetraploid origin of X. laevis by partitioning its genome into two homoeologous subgenomes, marked by distinct families of 'fossil' transposable elements. On the basis of the activity of these elements and the age of hundreds of unitary pseudogenes, we estimate that the two diploid progenitor species diverged around 34 million years ago (Ma) and combined to form an allotetraploid around 17-18 Ma. More than 56% of all genes were retained in two homoeologous copies. Protein function, gene expression, and the amount of conserved flanking sequence all correlate with retention rates. The subgenomes have evolved asymmetrically, with one chromosome set more often preserving the ancestral state and the other experiencing more gene loss, deletion, rearrangement, and reduced gene expression.