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Introduction: Class II DNA transposable elements account for significant portions of eukaryotic genomes and contribute to genome evolution through their mobilization. To escape inactivating mutations and persist in the host genome over evolutionary time, these elements must be mobilized enough to result in additional copies. These elements utilize a “cut and paste” transposition mechanism that does not intrinsically include replication. However, elements such as the rice derived mPing element have been observed to increase in copy number over time. Methods: We used yeast transposition assays to test several parameters that could affect the excision and insertion of mPing and its related elements. This included development of novel strategies for measuring element insertion and sequencing insertion sites. Results: Increased transposase protein expression increased the mobilization frequency of a small (430 bp) element, while overexpression inhibition was observed for a larger (7,126 bp) element. Smaller element size increased both the frequency of excision and insertion of these elements. The effect of yeast ploidy on element excision, insertion, and copy number provided evidence that homology dependent repair allows for replicative transposition. These elements were found to preferentially insert into yeast rDNA repeat sequences. Discussion: Identifying the parameters that influence transposition of these elements will facilitate their use for gene discovery and genome editing. These insights in to the behavior of these elements also provide important clues into how class II transposable elements have shaped eukaryotic genomes. 

Summary Crassulacean acid metabolism (CAM) photosynthesis has evolved repeatedly across the plant tree of life, however our understanding of the genetic convergence across independent origins remains hampered by the lack of comparative studies. Here, we explore gene expression profiles in eight species from the Agavoideae (Asparagaceae) encompassing three independent origins of CAM.Using comparative physiology and transcriptomics, we examined the variable modes of CAM in this subfamily and the changes in gene expression across time of day and between well watered and drought‐stressed treatments. We further assessed gene expression and the molecular evolution of genes encoding phosphoenolpyruvate carboxylase (PPC), an enzyme required for primary carbon fixation in CAM.Most time‐of‐day expression profiles are largely conserved across all eight species and suggest that large perturbations to the central clock are not required for CAM evolution. By contrast, transcriptional response to drought is highly lineage specific.YuccaandBeschorneriahave CAM‐like expression ofPPC2, a copy ofPPCthat has never been shown to be recruited for CAM in angiosperms.Together the physiological and transcriptomic comparison of closely related C₃and CAM species reveals similar gene expression profiles, with the notable exception of differential recruitment of carboxylase enzymes for CAM function.