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Simple Summary: Bees are one of the mega-diverse class of insects in Hymenoptera. As predators and the main crops pollinator, bees play an essential role in improving crop yield and the quality whiles providing substantial economic importance. Transposable elements (TEs) exist widely in nature and they make up a significant portion of prokaryotic and eukaryotic genomes. piggyBac (PB) transposons, belonging to DNA transposons, have been identified in plants, fungi, and animals. The advantages of the modified PB transposon system or high transposable efficiency and broad host ranges have led to their widespread application in transgenesis, mutagenesis, and gene therapy. At present, there is no systematic report on PB transposon in bees. Therefore, this study focused on annotating the transposons of the PB superfamily in bees to reveal the distribution, diversity, structural characteristics, evolutionary pattern and activity of PB transposons in the available genomes of bees. In this study, we investigated the presence of piggyBac (PB) transposons in 44 bee genomes from the Apoidea order, which is a superfamily within the Hymenoptera, which includes a large number of bee species crucial for pollination. We annotated the PB transposons in these 44 bee genomes and examined their evolution profiles, including structural characteristics, distribution, diversity, activity, and abundance. The mined PB transposons were divided into three clades, with uneven distribution in each genus of PB transposons in Apoidea. The complete PB transposons we discovered are around 2.23–3.52 kb in length and encode transposases of approximately 580 aa, with terminal inverted repeats (TIRs) of about 14 bp and 4 bp (TTAA) target-site duplications. Long TIRs (200 bp, 201 bp, and 493 bp) were also detected in some species of bees. The DDD domains of the three transposon types were more conserved, while the other protein domains were less conserved. Generally, most PB transposons showed low abundance in the genomes of Apoidea. Divergent evolution dynamics of PB were observed in the genomes of Apoidea. PB transposons in some identified species were relatively young, whiles others were older and with some either active or inactive. In addition, multiple invasions of PB were also detected in some genomes of Apoidea. Our findings highlight the contribution of PB transposons to genomic variation in these species and suggest their potential as candidates for future gene transfer tools. [ABSTRACT FROM AUTHOR]

Type-V-F Cas12f proteins, also known as Cas14, have drawn significant interest within the diverse CRISPR-Cas nucleases due to their compact size. This study involves analyzing and comparing Cas14-homology proteins in prokaryotic genomes through mining, sequence comparisons, a phylogenetic analysis, and an array/repeat analysis. In our analysis, we identified and mined a total of 93 Cas14-homology proteins that ranged in size from 344 aa to 843 aa. The majority of the Cas14-homology proteins discovered in this analysis were found within the Firmicutes group, which contained 37 species, representing 42% of all the Cas14-homology proteins identified. In archaea, the DPANN group had the highest number of species containing Cas14-homology proteins, a total of three species. The phylogenetic analysis results demonstrate the division of Cas14-homology proteins into three clades: Cas14-A, Cas14-B, and Cas14-U. Extensive similarity was observed at the C-terminal end (CTD) through a domain comparison of the three clades, suggesting a potentially shared mechanism of action due to the presence of cutting domains in that region. Additionally, a sequence similarity analysis of all the identified Cas14 sequences indicated a low level of similarity (18%) between the protein variants. The analysis of repeats/arrays in the extended nucleotide sequences of the identified Cas14-homology proteins highlighted that 44 out of the total mined proteins possessed CRISPR-associated repeats, with 20 of them being specific to Cas14. Our study contributes to the increased understanding of Cas14 proteins across prokaryotic genomes. These homologous proteins have the potential for future applications in the mining and engineering of Cas14 proteins. [ABSTRACT FROM AUTHOR]

Simple Summary: Transposable elements, including DNA transposons, play a significant role in genetic material exchanges between prokaryotes and eukaryotes. Comparative profiling of the evolution pattern of DNA transposons between prokaryotes and eukaryotes may identify potential genetic material exchanges between them and provide insights into the evolutionary history of prokaryotic and eukaryotic genomes. The members of the IS630-Tc1-mariner (ITm) group may represent the most diverse and widely distributed DNA transposons in nature, and the discovery of new members of this group is highly expected based on the increasing availability of genome sequencing data. We discovered a new superfamily (termed Sailor) belonging to the ITm hyperfamily, which differed from the known superfamilies of Tc1/mariner, DDxD/pogo and DD34E/Gambol, regarding phylogenetic position and catalytic domain. Our data revealed that Sailor was distributed in both prokaryotes and eukaryotes and suggested that horizontal transfer (HT) events of Sailor may occur from prokaryotic to eukaryotic genomes. Finally, internal transmissions of Sailor in prokaryotes and eukaryotes were also detected. Here, a new superfamily of IS630-Tc1-mariner (ITm) DNA transposons, termed Sailor, is identified, that is characterized by a DD82E catalytic domain and is distinct from all previously known superfamilies of the ITm group. Phylogenetic analyses revealed that Sailor forms a monophyletic clade with a more intimate link to the clades of Tc1/mariner and DD34E/Gambol. Sailor was detected in both prokaryotes and eukaryotes and invaded a total of 256 species across six kingdoms. Sailor is present in nine species of bacteria, two species of plantae, four species of protozoa, 23 species of Chromista, 12 species of Fungi and 206 species of animals. Moreover, Sailor is extensively distributed in invertebrates (a total of 206 species from six phyla) but is absent in vertebrates. Sailor transposons are 1.38–6.98 kb in total length and encoded transposases of ~676 aa flanked by TIRs with lengths between 18, 1362 and 4 bp (TATA) target-site duplications. Furthermore, our analysis provided strong evidence of Sailor transmissions from prokaryotes to eukaryotes and internal transmissions in both. These data update the classification of the ITm group and will contribute to the understanding of the evolution of ITm transposons and that of their hosts. [ABSTRACT FROM AUTHOR]