Time-calibrated phylogenetic and chromosomal mobilome analyses of Staphylococcus aureus CC398 reveal geographical and host-related evolution.

An international collection of Staphylococcus aureus of clonal complex (CC) 398 from diverse hosts spanning all continents and a 30 year-period is studied based on whole-genome sequencing (WGS) data. The collection consists of publicly available genomic data from 2994 strains and 134 recently sequenced Swiss methicillin-resistant S. aureus (MRSA) CC398 strains. A time-calibrated phylogeny reveals the presence of distinct phylogroups present in Asia, North and South America and Europe. European MRSA diverged from methicillin-susceptible S. aureus (MSSA) at the beginning of the 1950s. Two major European phylogroups (EP4 and EP5), which diverged approximately 1974, are the main drivers of MRSA CC398 spread in Europe. Within EP5, an emergent MRSA lineage spreading among the European horse population (EP5-Leq) diverged approximately 1996 from the pig lineage (EP5-Lpg), and also contains human-related strains. EP5-Leq is characterized by staphylococcal cassette chromosome mec (SCCmec) IVa and spa type t011 (CC398-IVa-t011), and EP5-Lpg by CC398-SCCmecVc-t011. The lineage-specific antibiotic resistance and virulence gene patterns are mostly mediated by the acquisition of mobile genetic elements like SCCmec, S. aureus Genomic Islands (SaGIs), prophages and transposons. Different combinations of virulence factors are present on S. aureus pathogenicity islands (SaPIs), and novel antimicrobial resistance gene containing elements are associated with certain lineages expanding in Europe. This WGS-based analysis reveals the actual evolutionary trajectory and epidemiological trend of the international MRSA CC398 population considering host, temporal, geographical and molecular factors. It provides a baseline for global WGS-based One-Health studies of adaptive evolution of MRSA CC398 as well as for local outbreak investigations.

Revisiting the evolution of bow-tie architecture in signaling networks.

Bow-tie architecture is a layered network structure that has a narrow middle layer with multiple inputs and outputs. Such structures are widely seen in the molecular networks in cells, suggesting that a universal evolutionary mechanism underlies the emergence of bow-tie architecture. The previous theoretical studies have implemented evolutionary simulations of the feedforward network to satisfy a given input-output goal and proposed that the bow-tie architecture emerges when the ideal input-output relation is given as a rank-deficient matrix with mutations in network link intensities in a multiplicative manner. Here, we report that the bow-tie network inevitably appears when the link intensities representing molecular interactions are small at the initial condition of the evolutionary simulation, regardless of the rank of the goal matrix. Our dynamical system analysis clarifies the mechanisms underlying the emergence of the bow-tie structure. Further, we demonstrate that the increase in the input-output matrix reduces the width of the middle layer, resulting in the emergence of bow-tie architecture, even when evolution starts from large link intensities. Our data suggest that bow-tie architecture emerges as a side effect of evolution rather than as a result of evolutionary adaptation.

The Structural Biology of Catalase Evolution.

Catalases are essential enzymes for removal of hydrogen peroxide, enabling aerobic and anaerobic metabolism in an oxygenated atmosphere. Monofunctional heme catalases, catalase-peroxidases, and manganese catalases, evolved independently more than two billion years ago, constituting a classic example of convergent evolution. Herein, the diversity of catalase sequences is analyzed through sequence similarity networks, providing the context for sequence distribution of major catalase families, and showing that many divergent catalase families remain to be experimentally studied.

Genome-wide identification of the sorghum OVATE gene family and revelation of its expression characteristics in sorghum seeds and leaves.

The OVATE gene family plays an important role in regulating the development of plant organs and resisting stress, but its expression characteristics and functions in sorghum have not been revealed. In this study, we identified 26 OVATE genes in the sorghum BTx623 genome, which were divided into four groups and distributed unevenly across 9 chromosomes. Evolutionary analysis showed that after differentiation between sorghum and Arabidopsis, the OVATE gene family may have experienced unique expansion events, and all OVATE family members were negatively selected. Transcriptome sequencing and RT-qPCR results showed that OVATE genes in sorghum showed diverse expression characteristics, such as gene SORBl_3001G468900 and SORBl_3009G173400 were significantly expressed in seeds, while SORBI_3005G042700 and SORBI_3002G417700 were only highly expressed in L1. Meantime, in the promoter region, a large number of hormone-associated cis-acting elements were identified, and these results suggest that members of the OVATE gene family may be involved in regulating specific development of sorghum leaves and seeds. This study improves the understanding of the OVATE gene family of sorghum and provides important clues for further exploration of the function of the OVATE gene family.

Phylogenomic analysis and dynamic evolution of chloroplast genomes of Clematis nannophylla.

Clematis nannophylla is a perennial shrub of Clematis with ecological, ornamental, and medicinal value, distributed in the arid and semi-arid areas of northwest China. This study successfully determined the chloroplast (cp) genome of C. nannophylla, reconstructing a phylogenetic tree of Clematis. This cp genome is 159,801 bp in length and has a typical tetrad structure, including a large single-copy, a small single-copy, and a pair of reverse repeats (IRa and IRb). It contains 133 unique genes, including 89 protein-coding, 36 tRNA, and 8 rRNA genes. Additionally, 66 simple repeat sequences, 50 dispersed repeats, and 24 tandem repeats were found; many of the dispersed and tandem repeats were between 20-30 bp and 10-20 bp, respectively, and the abundant repeats were located in the large single copy region. The cp genome was relatively conserved, especially in the IR region, where no inversion or rearrangement was observed, further revealing that the coding regions were more conserved than the noncoding regions. Phylogenetic analysis showed that C. nannophylla is more closely related to C. fruticosa and C. songorica. Our analysis provides reference data for molecular marker development, phylogenetic analysis, population studies, and cp genome processes to better utilise C. nannophylla.

Identification and expression analysis of Sox family genes in echinoderms.

The Sox gene family, a collection of transcription factors widely distributed throughout the animal kingdom, plays a crucial role in numerous developmental processes. Echinoderms occupy a pivotal position in many research fields, such as neuroscience, sex determination and differentiation, and embryonic development. However, to date, no comprehensive study has been conducted to characterize and analyze Sox genes in echinoderms. In the present study, the evolution and expression of Sox family genes across 11 echinoderms were analyzed using bioinformatics methods. The results revealed a total of 70 Sox genes, with counts ranging from 5 to 8 across different echinoderms. Phylogenetic analysis revealed that the identified Sox genes could be categorized into seven distinct classes: the SoxB1 class, SoxB2 class, SoxC class, SoxD class, SoxE class, SoxF class and SoxH class. Notably, the SoxB1, SoxB2, and SoxF genes were ubiquitously present in all the echinoderms studied, which suggests that these genes may be conserved in echinoderms. The spatiotemporal expression patterns observed for Sox genes in the three echinoderms indicated that various Sox members perform distinct functional roles. Notably, SoxB1 is likely involved in echinoderm ovary development, while SoxH may play a crucial role in testis development in starfish and sea cucumber. In general, the present investigation provides a molecular foundation for exploring the Sox gene in echinoderms, providing a valuable resource for future phylogenetic and genomic studies.

Exploring selection signatures in the divergence and evolution of lipid droplet (LD) associated genes in major oilseed crops.

BACKGROUND: Oil bodies or lipid droplets (LDs) in the cytosol are the subcellular storage compartments of seeds and the sites of lipid metabolism providing energy to the germinating seeds. Major LD-associated proteins are lipoxygenases, phospholipaseD, oleosins, TAG-lipases, steroleosins, caleosins and SEIPINs; involved in facilitating germination and enhancing peroxidation resulting in off-flavours. However, how natural selection is balancing contradictory processes in lipid-rich seeds remains evasive. The present study was aimed at the prediction of selection signatures among orthologous clades in major oilseeds and the correlation of selection effect with gene expression. RESULTS: The LD-associated genes from the major oil-bearing crops were analyzed to predict natural selection signatures in phylogenetically close-knit ortholog clusters to understand adaptive evolution. Positive selection was the major force driving the evolution and diversification of orthologs in a lineage-specific manner. Significant positive selection effects were found in 94 genes particularly in oleosin and TAG-lipases, purifying with excess of non-synonymous substitution in 44 genes while 35 genes were neutral to selection effects. No significant selection impact was noticed in Brassicaceae as against LOX genes of oil palm. A heavy load of deleterious mutations affecting selection signatures was detected in T-lineage oleosins and LOX genes of Arachis hypogaea. The T-lineage oleosin genes were involved in mainly anther, tapetum and anther wall morphogenesis. In Ricinus communis and Sesamum indicum > 85% of PLD genes were under selection whereas selection pressures were low in Brassica juncea and Helianthus annuus. Steroleosin, caleosin and SEIPINs with large roles in lipid droplet organization expressed mostly in seeds and were under considerable positive selection pressures. Expression divergence was evident among paralogs and homeologs with one gene attaining functional superiority compared to the other. The LOX gene Glyma.13g347500 associated with off-flavor was not expressed during germination, rather its paralog Glyma.13g347600 showed expression in Glycine max. PLD-α genes were expressed on all the tissues except the seed,δ genes in seed and meristem while ß and γ genes expressed in the leaf. CONCLUSIONS: The genes involved in seed germination and lipid metabolism were under strong positive selection, although species differences were discernable. The present study identifies suitable candidate genes enhancing seed oil content and germination wherein directional selection can become more fruitful.

Genome-wide identification and expression pattern analysis of MIKC-Type MADS-box genes in Chionanthus retusus, an androdioecy plant.

BACKGROUND: The MADS-box gene family is widely distributed in the plant kingdom, and its members typically encoding transcription factors to regulate various aspects of plant growth and development. In particular, the MIKC-type MADS-box genes play a crucial role in the determination of floral organ development and identity recognition. As a type of androdioecy plant, Chionanthus retusus have unique gender differentiation. Manifested as male individuals with only male flowers and female individuals with only bisexual flowers. However, due to the lack of reference genome information, the characteristics of MIKC-type MADS-box genes in C. retusus and its role in gender differentiation of C. retusus remain largely unknown. Therefore, it is necessary to identify and characterize the MADS-box gene family within the genome of the C. retusus. RESULTS: In this study, we performed a genome-wide identification and analysis of MIKC-type MADS-box genes in C. retusus (2n = 2x = 46), utilizing the latest reference genome, and studied its expression pattern in individuals of different genders. As a result, we identified a total of 61 MIKC-type MADS-box genes in C. retusus. 61 MIKC-type MADS-box genes can be divided into 12 subfamilies and distributed on 18 chromosomes. Genome collinearity analysis revealed their conservation in evolution, while gene structure, domains and motif analysis indicated their conservation in structure. Finally, based on their expression patterns in floral organs of different sexes, we have identified that CrMADS45 and CrMADS60 may potentially be involved in the gender differentiation of C. retusus. CONCLUSIONS: Our studies have provided a general understanding of the conservation and characteristics of the MIKC-type MADS-box genes family in C. retusus. And it has been demonstrated that members of the AG subfamily, CrMADS45 and CrMADS60, may play important roles in the gender differentiation of C. retusus. This provides a reference for future breeding efforts to improve flower types in C. retusus and further investigate the role of MIKC-type MADS-box genes in gender differentiation.

Understanding the Genetic Basis of Variation in Meiotic Recombination: Past, Present, and Future.

Meiotic recombination is a fundamental feature of sexually reproducing species. It is often required for proper chromosome segregation and plays important role in adaptation and the maintenance of genetic diversity. The molecular mechanisms of recombination are remarkably conserved across eukaryotes, yet meiotic genes and proteins show substantial variation in their sequence and function, even between closely related species. Furthermore, the rate and distribution of recombination shows a huge diversity within and between chromosomes, individuals, sexes, populations, and species. This variation has implications for many molecular and evolutionary processes, yet how and why this diversity has evolved is not well understood. A key step in understanding trait evolution is to determine its genetic basis-that is, the number, effect sizes, and distribution of loci underpinning variation. In this perspective, I discuss past and current knowledge on the genetic basis of variation in recombination rate and distribution, explore its evolutionary implications, and present open questions for future research.

RNA-guided RNA silencing by an Asgard archaeal Argonaute.

Argonaute proteins are the central effectors of RNA-guided RNA silencing pathways in eukaryotes, playing crucial roles in gene repression and defense against viruses and transposons. Eukaryotic Argonautes are subdivided into two clades: AGOs generally facilitate miRNA- or siRNA-mediated silencing, while PIWIs generally facilitate piRNA-mediated silencing. It is currently unclear when and how Argonaute-based RNA silencing mechanisms arose and diverged during the emergence and early evolution of eukaryotes. Here, we show that in Asgard archaea, the closest prokaryotic relatives of eukaryotes, an evolutionary expansion of Argonaute proteins took place. In particular, a deep-branching PIWI protein (HrAgo1) encoded by the genome of the Lokiarchaeon 'Candidatus Harpocratesius repetitus' shares a common origin with eukaryotic PIWI proteins. Contrasting known prokaryotic Argonautes that use single-stranded DNA as guides and/or targets, HrAgo1 mediates RNA-guided RNA cleavage, and facilitates gene silencing when expressed in human cells and supplied with miRNA precursors. A cryo-EM structure of HrAgo1, combined with quantitative single-molecule experiments, reveals that the protein displays structural features and target-binding modes that are a mix of those of eukaryotic AGO and PIWI proteins. Thus, this deep-branching archaeal PIWI may have retained an ancestral molecular architecture that preceded the functional and mechanistic divergence of eukaryotic AGOs and PIWIs.

Phylogenetic Survival Analysis.

Going back in time through a phylogenetic tree makes it possible to evaluate ancestral genomes and assess their potential to acquire key polymorphisms of interest over evolutionary time. Knowledge of this kind may allow for the emergence of key traits to be predicted and pre-empted from currently circulating strains in the future. Here, we present a novel genome-wide survival analysis and use the emergence of drug resistance in Mycobacterium tuberculosis as an example to demonstrate the potential and utility of the technique.

Functional and evolutionary comparative analysis of the DIR gene family in Nicotiana tabacum L. and Solanum tuberosum L.

BACKGROUND: The dirigent (DIR) genes encode proteins that act as crucial regulators of plant lignin biosynthesis. In Solanaceae species, members of the DIR gene family are intricately related to plant growth and development, playing a key role in responding to various biotic and abiotic stresses. It will be of great application significance to analyze the DIR gene family and expression profile under various pathogen stresses in Solanaceae species. RESULTS: A total of 57 tobacco NtDIRs and 33 potato StDIRs were identified based on their respective genome sequences. Phylogenetic analysis of DIR genes in tobacco, potato, eggplant and Arabidopsis thaliana revealed three distinct subgroups (DIR-a, DIR-b/d and DIR-e). Gene structure and conserved motif analysis showed that a high degree of conservation in both exon/intron organization and protein motifs among tobacco and potato DIR genes, especially within members of the same subfamily. Total 8 pairs of tandem duplication genes (3 pairs in tobacco, 5 pairs in potato) and 13 pairs of segmental duplication genes (6 pairs in tobacco, 7 pairs in potato) were identified based on the analysis of gene duplication events. Cis-regulatory elements of the DIR promoters participated in hormone response, stress responses, circadian control, endosperm expression, and meristem expression. Transcriptomic data analysis under biotic stress revealed diverse response patterns among DIR gene family members to pathogens, indicating their functional divergence. After 96 h post-inoculation with Ralstonia solanacearum L. (Ras), tobacco seedlings exhibited typical symptoms of tobacco bacterial wilt. The qRT-PCR analysis of 11 selected NtDIR genes displayed differential expression pattern in response to the bacterial pathogen Ras infection. Using line 392278 of potato as material, typical symptoms of potato late blight manifested on the seedling leaves under Phytophthora infestans infection. The qRT-PCR analysis of 5 selected StDIR genes showed up-regulation in response to pathogen infection. Notably, three clustered genes (NtDIR2, NtDIR4, StDIR3) exhibited a robust response to pathogen infection, highlighting their essential roles in disease resistance. CONCLUSION: The genome-wide identification, evolutionary analysis, and expression profiling of DIR genes in response to various pathogen infection in tobacco and potato have provided valuable insights into the roles of these genes under various stress conditions. Our results could provide a basis for further functional analysis of the DIR gene family under pathogen infection conditions.

Genomic diversity and evolutionary dynamics of Influenza A viruses in Colombian swine: implications for one health surveillance and control.

Influenza A viruses (IAV) impose significant respiratory disease burdens in both swine and humans worldwide, with frequent human-to-swine transmission driving viral evolution in pigs and highlighting the risk at the animal-human interface. Therefore, a comprehensive One Health approach (interconnection among human, animal, and environmental health) is needed for IAV prevention, control, and response. Animal influenza genomic surveillance remains limited in many Latin American countries, including Colombia. To address this gap, we genetically characterized 170 swine specimens from Colombia (2011-2017). Whole genome sequencing revealed a predominance of pandemic-like H1N1 lineage, with a minority belonging to H3N2 and H1N2 human seasonal-like lineage and H1N1 early classical swine lineages. Significantly, we have identified reassortant and recombinant viruses (H3N2, H1N1) not previously reported in Colombia. This suggests a broad genotypic viral diversity, likely resulting from reassortment between classical endemic viruses and new introductions established in Colombia's swine population (e.g. the 2009 H1N1 pandemic). Our study highlights the importance of a One Health approach in disease control, particularly in an ecosystem where humans are a main source of IAV to swine populations, and emphasizes the need for continued surveillance and enhanced biosecurity measures. The co-circulation of multiple subtypes in regions with high swine density facilitates viral exchange, underscoring the importance of monitoring viral evolution to inform vaccine selection and public health policies locally and globally.

Genome-Wide Gene Birth-Death Dynamics Are Associated with Diet Breadth Variation in Lepidoptera.

Comparative analyses of gene birth-death dynamics have the potential to reveal gene families that played an important role in the evolution of morphological, behavioral, or physiological variation. Here, we used whole genomes of 30 species of butterflies and moths to identify gene birth-death dynamics among the Lepidoptera that are associated with specialist or generalist feeding strategies. Our work advances this field using a uniform set of annotated proteins for all genomes, investigating associations while correcting for phylogeny, and assessing all gene families rather than a priori subsets. We discovered that the sizes of several important gene families (e.g. those associated with pesticide resistance, xenobiotic detoxification, and/or protein digestion) are significantly correlated with diet breadth. We also found 22 gene families showing significant shifts in gene birth-death dynamics at the butterfly (Papilionoidea) crown node, the most notable of which was a family of pheromone receptors that underwent a contraction potentially linked with a shift to visual-based mate recognition. Our findings highlight the importance of uniform annotations, phylogenetic corrections, and unbiased gene family analyses in generating a list of candidate genes that warrant further exploration.

Irreducible Complexity of Hox Gene: Path to the Canonical Function of the Hox Cluster.

The evolution of major taxa is often associated with the emergence of new gene families. In all multicellular animals except sponges and comb jellies, the genomes contain Hox genes, which are crucial regulators of development. The canonical function of Hox genes involves colinear patterning of body parts in bilateral animals. This general function is implemented through complex, precisely coordinated mechanisms, not all of which are evolutionarily conserved and fully understood. We suggest that the emergence of this regulatory complexity was preceded by a stage of cooperation between more ancient morphogenetic programs or their individual elements. Footprints of these programs may be present in modern animals to execute non-canonical Hox functions. Non-canonical functions of Hox genes are involved in maintaining terminal nerve cell specificity, autophagy, oogenesis, pre-gastrulation embryogenesis, vertical signaling, and a number of general biological processes. These functions are realized by the basic properties of homeodomain protein and could have triggered the evolution of ParaHoxozoa and Nephrozoa subsequently. Some of these non-canonical Hox functions are discussed in our review.

Plastome evolution of Engelhardia facilitates phylogeny of Juglandaceae.

BACKGROUND: Engelhardia (Juglandaceae) is a genus of significant ecological and economic importance, prevalent in the tropics and subtropics of East Asia. Although previous efforts based on multiple molecular markers providing profound insights into species delimitation and phylogeography of Engelhardia, the maternal genome evolution and phylogeny of Engelhardia in Juglandaceae still need to be comprehensively evaluated. In this study, we sequenced plastomes from 14 samples of eight Engelhardia species and the outgroup Rhoiptelea chiliantha, and incorporated published data from 36 Juglandaceae and six outgroup species to test phylogenetic resolution. Moreover, comparative analyses of the plastomes were conducted to investigate the plastomes evolution of Engelhardia and the whole Juglandaceae family. RESULTS: The 13 Engelhardia plastomes were highly similar in genome size, gene content, and order. They exhibited a typical quadripartite structure, with lengths from 161,069 bp to 162,336 bp. Three mutation hotspot regions (TrnK-rps16, ndhF-rpl32, and ycf1) could be used as effective molecular markers for further phylogenetic analyses and species identification. Insertion and deletion (InDels) may be an important driving factor for the evolution of plastomes in Juglandoideae and Engelhardioideae. A total of ten codons were identified as the optimal codons in Juglandaceae. The mutation pressure mostly contributed to shaping codon usage. Seventy-eight protein-coding genes in Juglandaceae experienced relaxed purifying selection, only rpl22 and psaI genes showed positive selection (Ka/Ks > 1). Phylogenetic results fully supported Engelhardia as a monophyletic group including two sects and the division of Juglandaceae into three subfamilies. The Engelhardia originated in the Late Cretaceous and diversified in the Late Eocene, and Juglandaceae originated in the Early Cretaceous and differentiated in Middle Cretaceous. The phylogeny and divergence times didn't support rapid radiation occurred in the evolution history of Engelhardia. CONCLUSION: Our study fully supported the taxonomic treatment of at the section for Engelhardia species and three subfamilies for Juglandaceae and confirmed the power of phylogenetic resolution using plastome sequences. Moreover, our results also laid the foundation for further studying the course, tempo and mode of plastome evolution of Engelhardia and the whole Juglandaceae family.

Genomic sequencing reveals convergent adaptation during experimental evolution in two budding yeast species.

Convergent evolution is central in the origins of multicellularity. Identifying the basis for convergent multicellular evolution is challenging because of the diverse evolutionary origins and environments involved. Haploid Kluyveromyces lactis populations evolve multicellularity during selection for increased settling in liquid media. Strong genomic and phenotypic convergence is observed between K. lactis and previously selected S. cerevisiae populations under similar selection, despite their >100-million-year divergence. We find K. lactis multicellularity is conferred by mutations in genes ACE2 or AIM44, with ACE2 being predominant. They are a subset of the six genes involved in the S. cerevisiae multicellularity. Both ACE2 and AIM44 regulate cell division, indicating that the genetic convergence is likely due to conserved cellular replication mechanisms. Complex population dynamics involving multiple ACE2/AIM44 genotypes are found in most K. lactis lineages. The results show common ancestry and natural selection shape convergence while chance and contingency determine the degree of divergence.

Graph-based mitochondrial genomes of three foundation species in the Saccharum genus.

KEY MESSAGE: We reported the graph-based mitochondrial genomes of three foundation species (Saccharum spontaneum, S. robustum and S. officinarum) for the first time. The results revealed pan-structural variation and evolutionary processes in the mitochondrial genomes within Saccharum. Saccharum belongs to the Andropogoneae, and cultivars species in Saccharum contribute nearly 80% of sugar production in the world. To explore the genomic studies in Saccharum, we assembled 15 complete mitochondrial genomes (mitogenome) of three foundation species (Saccharum spontaneum, S. robustum and S. officinarum) using Illumina and Oxford Nanopore Technologies sequencing data. The mitogenomes of the three species were divided into a total of eight types based on contig numbers and linkages. All mitogenomes in the three species encoded 51 unique genes, including 32 protein-coding, 3 ribosomal RNA (rRNA) and 16 transfer RNA (tRNA) genes. The existence of long and short-repeat-mediated recombinations in the mitogenome of S. officinarum and S. robustum was revealed and confirmed through PCR validation. Furthermore, employing comparative genomics and phylogenetic analyses of the organelle genomes, we unveiled the evolutionary relationships and history of the major interspecific lineages in Saccharum genus. Phylogenetic analyses of homologous fragments between S. officinarum and S. robustum showed that S. officinarum and S. robustum are phylogenetically distinct and that they were likely parallel rather than domesticated. The variations between ancient (S. sinense and S. barberi) and modern cultivated species (S. hybrid) possibly resulted from hybridization involving different S. officinarum accessions. Lastly, this project reported the first graph-based mitogenomes of three Saccharum species, and a systematic comparison of the structural organization, evolutionary processes, and pan-structural variation of the Saccharum mitogenomes revealed the differential features of the Saccharum mitogenomes.

Conservation of cis-Regulatory Syntax Underlying Deuterostome Gastrulation.

Throughout embryonic development, the shaping of the functional and morphological characteristics of embryos is orchestrated by an intricate interaction between transcription factors and cis-regulatory elements. In this study, we conducted a comprehensive analysis of deuterostome cis-regulatory landscapes during gastrulation, focusing on four paradigmatic species: the echinoderm Strongylocentrotus purpuratus, the cephalochordate Branchiostoma lanceolatum, the urochordate Ciona intestinalis, and the vertebrate Danio rerio. Our approach involved comparative computational analysis of ATAC-seq datasets to explore the genome-wide blueprint of conserved transcription factor binding motifs underlying gastrulation. We identified a core set of conserved DNA binding motifs associated with 62 known transcription factors, indicating the remarkable conservation of the gastrulation regulatory landscape across deuterostomes. Our findings offer valuable insights into the evolutionary molecular dynamics of embryonic development, shedding light on conserved regulatory subprograms and providing a comprehensive perspective on the conservation and divergence of gene regulation underlying the gastrulation process.

Overview and Evolution of Insect Fibroin Heavy Chain (FibH).

The FibH gene, crucial for silk spinning in insects, encodes a protein that significantly influences silk fiber mechanics. Due to its large size and repetitive sequences, limited known sequences of insect FibH impede comprehensive understanding. Here, we analyzed 114 complete FibH gene sequences from Lepidoptera (71 moths, 24 butterflies) and 13 Trichoptera, revealing single-copy FibH in most species, with 2-3 copies in Hesperinae and Heteropterinae (subfamily of skippers). All FibH genes are structured with two exons and one intron (39-45 bp), with the second exon being notably longer. Moths exhibit higher GC content in FibH compared to butterflies and Trichoptera. The FibH composition varies among species, with moths and butterflies favoring Ala, Gly, Ser, Pro, Gln, and Asn, while Trichoptera FibH is enriched in Gly, Ser, and Arg, and has less Ala. Unique to Trichoptera FibH are Tyr, Val, Arg, and Trp, whereas Lepidoptera FibH is marked by polyAla (polyalanine), polySer (polyserine), and the hexapeptide GAGSGA. A phylogenetic analysis suggests that Lepidoptera FibH evolved from Trichoptera, with skipper FibH evolving from Papilionoidea. This study substantially expands the FibH repertoire, providing a foundation for the development of artificial silk.