Abstract
BackgroundAsexual reproduction has the potential to enhance deleterious mutation accumulation and to constrain adaptive evolution. One source of mutations that can be especially relevant in recent asexuals is activity of transposable elements (TEs), which may have experienced selection for high transposition rates in sexual ancestor populations. Predictions of genomic divergence under asexual reproduction therefore likely include a large contribution of transposable elements but limited adaptive divergence. For plants empirical insight into genome divergence under asexual reproduction remains limited. Here, we characterize expression divergence between clone members of a single apomictic lineage of the common dandelion (Taraxacum officinale) to contribute to our knowledge of genome evolution under asexuality.ResultsUsing RNA-Seq, we show that about one third of heritable divergence within the apomictic lineage is driven by TEs and TE-related gene activity. In addition, we identify non-random transcriptional differences in pathways related to acyl-lipid and abscisic acid metabolisms which might reflect functional divergence within the apomictic lineage. We analyze SNPs in the transcriptome to assess genetic divergence between the apomictic clone members and reveal that heritable expression differences between the accessions are not explained simply by genome-wide genetic divergence.ConclusionThe present study depicts a first effort towards a more complete understanding of apomictic plant genome evolution. We identify abundant TE activity and ecologically relevant functional genes and pathways affecting heritable within-lineage expression divergence. These findings offer valuable resources for future work looking at epigenetic silencing and Cis-regulation of gene expression with particular emphasis on the effects of TE activity on asexual species’ genome.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-016-2524-6) contains supplementary material, which is available to authorized users.
Highlights
Asexual reproduction has the potential to enhance deleterious mutation accumulation and to constrain adaptive evolution
Additional file 3: Differentially expressed genes identified using DESeq, heritability index and annotations from SwissProt and Arabidopsis thaliana coding sequence databases for the semi-natural field experiment. (XLSX 9161 kb)
Additional file 4: Differentially expressed genes identified using DESeq, heritability index and annotations from SwissProt and Arabidopsis thaliana coding sequence databases for the greenhouse experiment. (XLSX 61 kb)
Summary
Asexual reproduction has the potential to enhance deleterious mutation accumulation and to constrain adaptive evolution. Predictions of genomic divergence under asexual reproduction likely include a large contribution of transposable elements but limited adaptive divergence. For plants empirical insight into genome divergence under asexual reproduction remains limited. Asexuality offers the ecological advantages of uniparental reproduction and enables the transmission of well-adapted gene combinations [3, 4]. It can be a less costly alternative to sexuality in sparsely inhabited, homogenous environments where abiotic factors dominate the selection regime [1, 5]. Sexual and asexual reproductions have different consequences for genome evolution, and much effort is spent on unravelling the evolutionary forces that shape genomes under the different modes of reproduction [6, 7]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
