The mutational load in natural populations is significantly affected by high primary rates of retroposition.

Affiliation

Zhang W(1), Xie C(1), Ullrich K(1), Zhang YE(2)(3), Tautz D(4).
Author information:
(1)Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, D-24306 Plön, Germany.
(2)Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, China.
(3)State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, China.
(4)Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, D-24306 Plön, Germany; [Email]

Abstract

Gene retroposition is known to contribute to patterns of gene evolution and adaptations. However, possible negative effects of gene retroposition remain largely unexplored since most previous studies have focused on between-species comparisons where negatively selected copies are mostly not observed, as they are quickly lost from populations. Here, we show for natural house mouse populations that the primary rate of retroposition is orders of magnitude higher than the long-term rate. Comparisons with single-nucleotide polymorphism distribution patterns in the same populations show that most retroposition events are deleterious. Transcriptomic profiling analysis shows that new retroposed copies become easily subject to transcription and have an influence on the expression levels of their parental genes, especially when transcribed in the antisense direction. Our results imply that the impact of retroposition on the mutational load has been highly underestimated in natural populations. This has additional implications for strategies of disease allele detection in humans.