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Mutational and Transcriptional Landscape of Spontaneous Gene Duplications and Deletions in Caenorhabditis elegans

ABSTRACT: Gene duplication and deletion are pivotal processes shaping the structural and functional repertoire of genomes, with implications for disease, adaptation and evolution. We employed an experimental evolution framework partnered with high-throughput genomics to assess the molecular and transcriptional characteristics of novel gene copy-number variants (CNVs) in Caenorhabditis elegans populations subjected to varying intensity of selection. Here, we report a direct spontaneous genome-wide rate of gene duplication of 2.9 × 10-5 /gene/generation in C. elegans, the highest for any species to date. The increase in average transcript abundance of new duplicates arising under minimal selection is significantly greater than two-fold compared to single-copies of the same gene, suggesting that genes in segmental duplications are frequently overactive at inception. The average increase in transcriptional activity of gene duplicates is greater in MA lines that passed through single individual bottlenecks than in MA lines with larger population bottlenecks. Furthermore, there is an inverse relationship between the ancestral transcription levels of newly originating gene duplicates and population size, with duplicate copies of highly expressed genes less likely to accumulate in larger populations. The results demonstrate that there is a fitness cost of superfluous gene expression and purifying selection against new gene duplicates. However, on average, duplications also provide a significant increase in gene expression that can facilitate adaptation to novel environmental challenges.

ORGANISM(S): Caenorhabditis elegans

PROVIDER: GSE112821 | GEO | 2018/04/07

REPOSITORIES: GEO

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