Processed pseudogenes are more abundant in human and mouse X chromosomes than in autosomes

Abstract

Two different hypotheses have been proposed to explain the observation that some genomes contain more processed pseudogenes than others. One predicts that processed pseudogene abundance is inversely proportional to the substrate specificity of the reverse transcriptase that generates processed pseudogenes. The other predicts that the amount of processed pseudogenes found in genomes is proportional to the length of oogenesis. Here, we test the oogenesis hypothesis by analyzing the data from 6 studies that described the number of pseudogenes on different chromosomes of the human and/or mouse genomes. Our results show a significant overabundance of processed pseudogenes in the X chromosomes and a significant underrepresentation of processed pseudogenes in the Y chromosome of the human genome. These observations support the hypothesis that the number of processed pseudogenes is proportional to the length of oogenesis. © The Author 2006. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved.