Nonadaptive hypotheses on the evolution of eukaryotic genome size predict an expansion when the process of purifying selection becomes weak. Accordingly, species with huge genomes, such as lungfish, are expected to show a genome-wide relaxation signature of selection compared with other organisms. However, few studies have empirically tested this prediction using genomic data in a comparative framework. Here, we show that 1) the newly assembled transcriptome of the Australian lungfish, Neoceratodus forsteri, is characterized by an excess of pervasive transcription, or transcriptional leakage, possibly due to suboptimal transcriptional control, and 2) a significant relaxation signature in coding genes in lungfish species compared with other vertebrates. Based on these observations, we propose that the largest known animal genomes evolved in a nearly neutral scenario where genome expansion is less efficiently constrained

Fuselli, S.; Greco, S.; Biello, R.; Palmitessa, S.; Lago, M.; Meneghetti, C.; Mcdougall, C.; Trucchi, E.; Rota Stabelli, O.; Biscotti, A.M.; Schmidt, D.J.; Roberts, D.T.; Espinoza, T.; Hughes, J.M.; Ometto, L.; Gerdol, M.; Bertorelle, G. (2023-09-01). Relaxation of natural selection in the evolution of the giant lungfish genomes. MOLECULAR BIOLOGY AND EVOLUTION, 40 (9): msad193. doi: 10.1093/molbev/msad193 handle: https://hdl.handle.net/10449/83376

Relaxation of natural selection in the evolution of the giant lungfish genomes

Rota Stabelli, Omar;
2023-09-01

Abstract

Nonadaptive hypotheses on the evolution of eukaryotic genome size predict an expansion when the process of purifying selection becomes weak. Accordingly, species with huge genomes, such as lungfish, are expected to show a genome-wide relaxation signature of selection compared with other organisms. However, few studies have empirically tested this prediction using genomic data in a comparative framework. Here, we show that 1) the newly assembled transcriptome of the Australian lungfish, Neoceratodus forsteri, is characterized by an excess of pervasive transcription, or transcriptional leakage, possibly due to suboptimal transcriptional control, and 2) a significant relaxation signature in coding genes in lungfish species compared with other vertebrates. Based on these observations, we propose that the largest known animal genomes evolved in a nearly neutral scenario where genome expansion is less efficiently constrained
Australian lungfish (Neoceratodus forsteri)
Genome size evolution
Lungfish
Pervasive transcription
Relaxation of natural selection
Settore BIO/11 - BIOLOGIA MOLECOLARE
1-set-2023
Fuselli, S.; Greco, S.; Biello, R.; Palmitessa, S.; Lago, M.; Meneghetti, C.; Mcdougall, C.; Trucchi, E.; Rota Stabelli, O.; Biscotti, A.M.; Schmidt, D.J.; Roberts, D.T.; Espinoza, T.; Hughes, J.M.; Ometto, L.; Gerdol, M.; Bertorelle, G. (2023-09-01). Relaxation of natural selection in the evolution of the giant lungfish genomes. MOLECULAR BIOLOGY AND EVOLUTION, 40 (9): msad193. doi: 10.1093/molbev/msad193 handle: https://hdl.handle.net/10449/83376
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10449/83376
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