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PubMed2026

Evidence for dual pathways of Tc1/mariner domestication in Drosophila.

BACKGROUND: The domestication of transposable elements is a key source of evolutionary innovation, yet the pathways by which their functional modules are repurposed by the host remain poorly understood. The Tc1/mariner superfamily is a widespread group of DNA transposons, but the prevalence and patterns of their domestication are underexplored. RESULTS: We performed a systematic genomic screen across 43 drosophilid species using stringent criteria for molecular domestication. This analysis identified five high-confidence, evolutionarily conserved genes derived from Tc1/mariner transposases. Phylogenetic and structural analyses suggest domestication via two distinct molecular pathways: co-option of the DNA-binding module and co-option of the catalytic domain. The DNA-binding module pathway includes CG4570, the previously known genes cag and toy (the latter fused with a homeodomain), and a lineage-restricted gene in the Drosophila obscura group that exhibits signatures of recent domestication. In contrast, the catalytic domain pathway is represented solely by CG14478. Structural modeling reveals that CG14478 protein preserves a canonical DDE endonuclease fold. Co-expression network analysis suggests potential cellular roles of these genes: CG14478 is linked to RNA/chromatin-related processes, CG4570 to cell cycle/chromosome functions, cag to ciliary and nuclear functions, and toy to neuronal development. CONCLUSIONS: This study establishes a stringent framework for identifying domesticated TEs, demonstrating that Tc1/mariner elements are co-opted via two distinct pathways: retention of either catalytic or DNA-binding modules. Our findings suggest that domestication is a dynamic continuum, ranging from recent, lineage-specific events to ancient, conserved genes, and underscore how genomic conflict with TEs can drive eukaryotic evolution and regulatory complexity.

Animals↗
PubMed2026

Genome-Wide Characterization of the Apple HD-Zip IV Gene Family and Functional Validation of MdHDZIV3 Under PEG-Induced Osmotic Stress.

The homeodomain-leucine zipper IV (HD-Zip IV) transcription factor subfamily plays essential roles in epidermal development, cuticle formation, lipid metabolism, and environmental adaptation in plants. Despite its biological importance, the HD-Zip IV family has not been systematically characterized in apple (Malus domestica). Here, we identified 17 apple HD-Zip IV genes and named them MdHDZIV1-MdHDZIV17 based on their locations on the chromosomes. The 17 genes showed a nonuniform distribution on eight chromosomes, while the occurrence of both tandem and segmental duplications indicated that family expansion involved more than one duplication mechanism. All MdHDZIV proteins contained the conserved HD, LZ, START, and SAD domains but lacked the MEKHLA domain, consistent with typical HD-Zip IV structural features. Phylogenetic analysis classified MdHDZIV proteins into five groups together with HD-Zip IV members from Arabidopsis thaliana and rice, indicating evolutionary conservation of this subfamily. Collinearity and Ka/Ks analyses revealed that duplicated MdHDZIV gene pairs were mainly subjected to purifying selection. Promoter scanning revealed diverse cis-regulatory motifs associated with hormonal signaling, environmental stress, light response, and epidermal regulation, including ABRE, ARE, W-box, MYC, G-box, and L1-box motifs. Integration of transcriptomic profiling with qRT-PCR validation revealed pronounced tissue-dependent differences in the expression of MdHDZIV genes in leaf, fruit skin, and branch bark. Under PEG6000-induced osmotic stress and NaCl-induced salt stress, 10 candidate MdHDZIV genes displayed gene-specific and stress type-specific expression patterns, with MdHDZIV3 showing strong induction under PEG6000 treatment. Functional validation in apple calli showed that MdHDZIV3 overexpression enhanced PEG tolerance, increased fresh weight, elevated SOD and POD activities, and reduced MDA accumulation under osmotic stress. These findings provide a genome-wide framework for understanding the apple HD-Zip IV gene family.

abiotic stress↗
PubMed1991

Primary structure and oxygen-binding properties of the hemoglobin from the lesser hedgehog tenrec (Echinops telfairi, Zalambdodonta). Evidence for phylogenetic isolation.

The primary structures of the alpha- and beta-hemoglobin chains of the lesser hedgehog tenrec (Echinops telfairi, Zalambdodonta) are presented. Chain separation was performed by carboxymethyl-cellulose chromatography. The peptides, obtained by tryptic digestion of the oxidized chains, were prefractionated by gel chromatography and isolated by reversed-phase HPLC. For sequence analysis gas and liquid phase sequencers were employed. The tenrec hemoglobin consists of one alpha- and two beta-chains the latter occurring in a 1:1 ratio and differing in beta 16 Gly/Cys and beta 118 Phe/Leu. Two external cysteine residues at beta 16 and beta 52 cause reversible polymerization to octamers and most likely irreversible formation of higher polymers. A comparison of the whole chains and certain positions of tenrec hemoglobin with those of Insectivora sensu strictu, Scandentia and Proto- and Metatheria corroborates a long and independent evolution of tenrec and its phylogenetic isolation from the Insectivora s.str. (hedgehog, musk shrew and mole). Replacements at positions involved in heme and subunit interface contacts are discussed. Compared to human hemoglobin the tenrec pigment shows a low intrinsic oxygen affinity as well as lower chloride and temperature sensitivities, a reduced Bohr effect and a strong response to 2,3-DPG. The possible adaptive significance of these properties is discussed in relation to the large diurnal body temperature variations seen in tenrecs.

Amino Acid Sequence↗
PubMedDate not supplied

[Neuronal reactions of the olfactory centers of the forebrain during stimulation of the hypothalamic structures in rabbits].

During stimulation of phylogenetically ancient parts of the hypothalamus (the anterior and lateral), neuronal reactions have been recorded in the prepyriform lobe and tuberculum olfactorium. These reactions are characterized by a short latent period (6-25 msec) and high stability to rhythmic stimulation. Neuronal reactions in the same olfactory centers during stimulation of phylogenetically more recent hypothalamic structures (the posterior and medial) exhibit a long latent period (30-120 msec) and are readily exhausted by rhythmic stimulation.

Animals↗
PubMed2025

Inference of Cytochrome P450 Evolutionary History Using Structural and Physicochemical Metrics.

Cytochrome P450s are a superfamily of heme-binding monooxygenases involved with the detoxification of intrinsic and extrinsic toxins. They are near ubiquitous within biological domains and are found in all domains. Members of families within the superfamily are defined based on amino acid identity thresholds, with thresholds as low as 40% in some families. Relationships among Cytochrome P450 families have proven elusive due to sub-Twilight Zone interfamily identities (<30%) that result in poor multiple sequence alignment quality and thus low levels of support for downstream phylogenetic reconstructions. Despite the low identities, Cytochrome P450 structures are remarkably well conserved both within and among families. In such cases, structural phylogenetics has the potential to unveil elusive relationships because the selectively favored physicochemical properties giving rise to the structure and function of the proteins persist despite sequence-level divergence. Recently, in two separate publications, we demonstrated that by utilizing physicochemical vectors, dynamic time warping, and hierarchical clustering (PCDTW), large swaths of protein domain families and betacoronavirus receptor-binding domain clades were congruent with validated functional/structural relationships. These were important findings because anomalous sequence alignment-based maximum likelihood phylogenetic findings, which were not congruent with the known functional relationships, were resolved. That also validated the use of physicochemical vectors in making inferences about structural/functional homology. Additionally, it illuminated that the same methods might be applied to other protein families with relationships that are difficult to resolve from sequence data alone. Herein, we used Molecular Weight and Hydrophobicity Physicochemical Dynamic Time Warping (MWHP PCDTW) along with structural and sequence alignment-based phylogenetic methodologies to analyze all of the Cytochrome P450s found both in the high-fidelity Structural Classificaction of Proteins (SCOP) database and the reviewed sequences with both experimentally resolved and de novo predicted structures in the Protein Data Bank and the AlphaFold (AF) Protein Structure Database, respectively. We compared the resulting phylogenetic topologies and found that in some cases, structure-based methods may be less able to resolve random/convergent similarity than physicochemical and sequence-based methodologies. This finding agrees with previous findings that demonstrate the usefulness of physicochemical properties in resolving both random structural similarity and potentially convergent relationships.

Cytochrome P-450 Enzyme System↗
PubMed2026

Mitochondrial genomes of Dactylogyrus wunderi (Monopisthocotyla: Dactylogyridae): structural features, codon usage patterns, and phylogenetic implications.

BACKGROUND: Codon usage bias (CUB) is a common phenomenon reported among many species and genes, but its unique characteristics in the mitochondrial genome of class Monopisthocotyla remain unknown. METHODS: The complete mitochondrial genome of Dactylogyrus wunderi was sequenced and characterized, and the mitochondrial genome compositions and CUB of six Dactylogyrus species and 35 Monopisthocotyla species were analyzed using bioinformatics methods. RESULTS: The mitochondrial genome of D. wunderi is a typical circular structure in length of 14,920 bp. The A&#x2009;+&#x2009;T contents of the six Dactylogyrus species (58.4% &#xb1; 5.7%) were significantly lower than that of Monopisthocotyla species (71.0% &#xb1; 5.80%, p&#x2009;<&#x2009;0.01). Neutrality plot analysis showed slopes of 0.3136 and 0.389 in the six Dactylogyrus and the 35 Monopisthocotyla species, respectively. Furthermore, 98.3% and 77.4% of the genes in the six Dactylogyrus and the Monopisthocotyla species, respectively, had effective number of codons (ENC) higher than 35, but 23.3% and 0.5% genes of ENC ratio ranged from -&#x2009;0.05 to 0.05 in the six Dactylogyrus and Monopisthocotyla species. Phylogenetic analysis revealed that, within the context of the sampled taxa, the families of Monopisthocotyla were monophyletic groups, except for Ancyrocephalidae. CONCLUSIONS: The nucleotide composition had AT base bias in Monopisthocotyla, and natural selection was the main factor affecting CUB in the mitochondrial genomes of Monopisthocotyla species. These results provided insights into the factors affecting CUB in Monopisthocotyla species and deepened our insight of phylogeny, evolution, and codon usage of Monopisthocotyla.

Genome, Mitochondrial↗
PubMed1990

Mutational analysis of conserved nucleotides in a self-splicing group I intron.

We have constructed all single base substitutions in almost all of the highly conserved residues of the Tetrahymena self-splicing intron. Mutation of highly conserved residues almost invariably leads to loss of enzymatic activity. In many cases, activity could be regained by making additional mutations that restored predicted base-pairings; these second site suppressors in general confirm the secondary structure derived from phylogenetic data. At several positions, our suppression data can be most readily explained by assuming non-Watson-Crick base-pairings. In addition to the requirements imposed by the secondary structure, the sequence of the intron is constrained by "negative interactions", the exclusion of particular nucleotide sequences that would form undesirable secondary structures. A comparison of genetic and phylogenetic data suggests sites that may be involved in tertiary structural interactions.

Animals↗
PubMed1991

Phylogenetic study of serotonin-immunoreactive structures in the pancreas of various vertebrates.

The distribution pattern of serotonin (5HT) in the pancreas was studied immunohistochemically by using a 5HT monoclonal antibody in various vertebrates including the eel, bullfrog, South African clawed toad, turtle, chicken, mouse, rat, guinea-pig, cat, dog and human. In all species examined, except the bullfrog, 5HT-like immunoreactivity was observed in nerve fibers, in endocrine cells, or in both. Positive nerve fibers were found in the eel, turtle, mouse, rat and guinea-pig. These fibers ran mainly along the blood vessels and partly through the gap between the exocrine glands. In the eel and guinea-pig, positive fibers invaded the pancreatic islet. Occasionally, these positive fibers were found adjacent to the surface of both exocrine and endocrine cells, suggesting a regulatory role of 5HT in pancreatic function. 5HT-positive endocrine cells were observed in the pancreas of all species except for the bullfrog and rat. In the eel and in mammals such as the mouse, guinea-pig, cat, dog and human, 5HT-positive cells were mainly observed within the pancreatic islet. In the South African clawed toad, turtle and chicken, the positive cells were mainly in the exocrine region. The present study indicates that the distribution patterns of 5HT in the pancreas varies considerably among different species.

Amphibians↗
PubMed1992

Characterization of the Bacillus subtilis rpsD regulatory target site.

The Bacillus subtilis rpsD gene, which encodes ribosomal protein S4, is subject to autogenous regulation. Repression of rpsD expression by excess S4 protein was previously shown to be affected by mutations in the leader region of the gene. A large number of deletion and point mutations in the leader region were generated, and their effect on repression by S4 in vivo was tested. These studies indicated that the required region was within positions +30 to +190 relative to the transcription start point. Replacement of the rpsD promoter with a lac promoter derivative which is expressed in B. subtilis had no effect, indicating that repression by S4 occurs at a level subsequent to transcription initiation. The rpsD leader region was isolated from several Bacillus species. Members of the B. subtilis group, as defined by analysis of 16S rRNA sequence, contained a leader region target site very closely related in structure to that of B. subtilis, despite considerable primary sequence variation; the B. brevis rpsD leader contained some but not all of the structural features found in the regulatory target sites of the other Bacillus species. Very little similarity to the Escherichia coli alpha operon S4 target site was found at either the primary-sequence or the secondary-structure level. Mutagenic and phylogenetic data indicate that the secondary structure of the leader region regulatory target site contains two large stem-loop domains. The first of these helices has a side loop which is essential for autoregulation, is highly conserved among Bacillus rpsD genes, and is similar to a region of 16S rRNA important in S4 binding.

Bacillus subtilis↗
PubMed1992

Structural features in TAR RNA of human and simian immunodeficiency viruses: a phylogenetic analysis.

A comparative analysis of TAR RNA structures in human and simian immunodeficiency viruses reveals the conservation of certain structural features despite the divergence in sequence. Both the TAR elements of HIV-1 and SIV-chimpanzee can be folded into relatively simple one-stem hairpin structures. Chemical and RNAase probes were used to analyze the more complex structure of HIV-2 TAR RNA, which folds into a branched hairpin structure. A surprisingly similar RNA conformation can be proposed for SIV-mandrill, despite considerable divergence in nucleotide sequence. A third structural presentation of TAR sequences is seen for SIV-african green monkey. These results are generally consistent with the classification of HIV-SIV viruses in four subgroups based on sequence analyses (both nucleotide- and amino acid-sequences). However, some conserved TAR structures were detected for members of different virus subgroups. It is therefore proposed that RNA structure analysis might provide an additional tool for determining phylogenetic relationships among the HIV-SIV viruses.

Base Composition↗
PubMedDate not supplied

[The dynamics of the electrical activity of the forebrain structures in rats in the waking-sleep cycle after electrostimulations of the emotiogenic zones in the lateral hypothalamic area].

One series of ES (multiple priming) of emotion-positive zone (1) ore the ambivalent zone (2) of lateral hypothalamus (LH) during one hour in Wistar male rats resulted in disorders of the W-S cycle: reduction of deep slow-wave sleep down to about 4.7% (zone 1) and down to 0.9% (zone 2), as well as a considerable reduction of REM sleep down to 0.8% (zone 1). The results of the analysis of bioelectrical brain activity dynamics in the W-S cycle suggest that hyperactivation of emotiogenic zones generated by ES is responsible for the establishment of paroxysmal states corresponding to the second and the third stages of kindling and the disorders of the W-S cycle. Kindling is assumed to form due to emotiogenic zones of the brain involved in to this process. The longer bursts of hypersynchronous bioelectrical activity in the cortex than in the subcortical structures during transient stages of sleep may be in favour of more active participation of phylogenetically younger brain structures in the process of epileptogenesis.

Animals↗
PubMed1976

Possible phylogenetical significance of the corpus callosum with special reference to the dolphin brain (Stenella graffmani).

The surface area of the corpus callosum was measured in several animals as compared to the brain weight. A general consideration of the importance of this structure on the phylogenetic scale, with special reference to the corpus callosum of the dolphin, Stenella graffmani, is given. Some theoretical considerations about the significance of this structure upon some specialized features are mentioned.

Anatomy, Comparative↗
PubMed1976

[Lung structure of Sphenodon punctatus. A comparative anatomic study].

After a critical review of the literature, the authors describe the structure of the lung of Sphenodon, dealing with form, arteries, veins, and septation. The external form, circulatory pattern, degree of complication, height of the septa, vascular structure, and decrease in complication (?) are discussed from the standpoint of comparative anatomy. In an attempt to explain the unusual findings, the capacity for development of the central and subpleural type of differentiation is compared and contrasted. Obvious relations between the unusual lung structure and the phylogenetic age of the Sphenodon were sought, with the conclusion that the Sphenodon cannot be included in the Reptilian oders since its physical structure forms a class by itself.

Animals↗
PubMed2025

Landscape genomics analysis reveals the genetic basis underlying cashmere goats and dairy goats adaptation to frigid environments.

Understanding the genetic mechanism of cold adaptation in cashmere goats and dairy goats is very important to improve their production performance. The purpose of this study was to comprehensively analyze the genetic basis of goat adaptation to cold environments, clarify the impact of environmental factors on genome diversity, and lay the foundation for breeding goat breeds to adapt to climate change. A total of 240 dairy goats were subjected to genome resequencing, and the whole genome sequencing data of 57 individuals from 6 published breeds were incorporated. By integrating multiple approaches such as phylogenetic analysis, population structure analysis, gene flow and population history exploration, selection signal analysis, and genome-environment association analysis, an in-depth investigation was carried out. Phylogenetic analysis unraveled the genetic relationships and differentiation patterns among dairy goats and other goat breeds. Through signal analysis (&#x3b8;&#x3c0;, FST, XP-CLR), we identified numerous candidate genes associated with cold adaptation in dairy goats (STRIP1, ALX3, HTR4, NTRK2, MRPL11, PELI3, DPP3, BBS1) and cashmere goats (MED12L, MARC2, MARC1, DSG3, C6H4orf22, CHD7, MYPN, KIAA0825, MITF). Genome-environment association (GEA) analysis confirmed the link between these genes and environmental factors. Moreover, a detailed analysis of the critical genes C6H4orf22 and STRIP1 demonstrated their significant roles in the geographical variations of cold adaptation and allele frequency differences among different breeds. This study contributes to understanding the genetic basis of cold adaptation, providing crucial theoretical support for precision breeding programs aimed at improving production performance in cold regions by leveraging adaptive alleles, thereby ensuring sustainable animal husbandry.

Environmental adaptation↗
PubMed2026

Plastid genome evolution and phylogenomics with broad taxon sampling: insights into intrafamilial classification of Hamamelidaceae.

Hamamelidaceae, within the order Saxifragales, comprises 27 genera and approximately 120 species. The family has a pantropical and temperate distribution across the Americas, Asia, Africa, and Australia. Previous molecular investigations, constrained by limited taxon sampling and inadequate genetic markers, supported a five-subfamily classification system. However, these studies predominantly focused on Asian taxa, resulting in poor resolution of the evolutionary relationships among American, African, and Australian genera. To address these sampling gaps, we employed near-complete generic sampling (26 of 27 genera) to investigate plastome architecture, structural variation, and phylogenetic relationships. We newly sequenced and assembled 15 plastid genomes representing geographically and taxonomically underrepresented genera and analyzed them alongside 59 publicly available plastomes retrieved from GenBank. Plastid genomes exhibited conserved quadripartite architecture with sizes ranging from 158, 076 bp to 160, 814 bp, minimal structural variation, consistent GC content (37.7-38.2%), and identical gene order. Inverted repeat (IR) regions had limited size variation (26, 211-26, 429 bp). Simple sequence repeat (SSR) distribution (2, 219 loci) showed no clear correlation with the genus-level phylogenetic relationships. We identified ten hypervariable regions, including coding sequences (accD, ycf1, clpP, ndhF, and rpl22) and intergenic spacers (rpl33-rps18, the trnG-UCC intron, trnH-GUG-psbA, accD-psaI, and petA-psbJ), as promising candidate regions for future applications in species delimitation and phylogenetic studies. Phylogenetic analyses revealed largely congruent topologies across datasets and methods, providing improved resolution and strong support for most subfamilial and tribal relationships compared with previous studies. This study highlights the utility of plastid genome data for resolving deep-level phylogenetic relationships within Hamamelidaceae. The genome architecture reflects the high conservation of plastid genomes, while the identified mutation hotspots represent potential resources for future taxonomic and phylogenetic studies. Our results support the existing subfamily classification while improving geographical coverage and generic representation, providing a robust framework for future taxonomic and evolutionary studies of this globally distributed and taxonomically complex family.

Hamamelidaceae↗
PubMed2025

Genetic and phenotypic diversity of wine-associated Hanseniaspora species.

The genus Hanseniaspora includes apiculate yeasts commonly found in fruit- and fermentation-associated environments. Their genetic diversity and evolutionary adaptations remain largely unexplored despite their ecological and oenological significance. This study investigated the phylogenetic relationships, genome structure, selection patterns, and phenotypic diversity of Hanseniaspora species isolated primarily from Australian wine environments, focusing on Hanseniaspora uvarum, the most abundant non-Saccharomyces yeast in wine fermentation. A total of 151 isolates were sequenced, including long-read genomes for representatives of the main phylogenetic clades. Comparative genomics revealed ancestral chromosomal rearrangements between the slow-evolving lineage (SEL) and fast-evolving lineage (FEL) that could have contributed to their evolutionary split, as well as significant loss of genes associated with mRNA splicing, chromatid segregation and signal recognition particle protein targeting in the FEL. Pangenome analysis within H. uvarum identified extensive copy number variation, particularly in genes related to xenobiotic tolerance and nutrient transport. Investigation into the selective landscape following the FEL/SEL divergence identified diversifying selection in 229 genes in the FEL, with significant enrichment in genes within the lysine biosynthetic pathway. Furthermore, phenotypic screening of 116 isolates revealed substantial intraspecific diversity, with specific species exhibiting enhanced ethanol, osmotic, copper, SO&#x2082;, and cold tolerance.

Wine↗
PubMed1992

Plus and minus RNAs of peach latent mosaic viroid self-cleave in vitro via hammerhead structures.

Peach latent mosaic viroid (PLMVd), the causal agent of peach latent mosaic disease, has been sequenced and found to be a circular RNA molecule of 337 nucleotide residues, which adopts a branched conformation when it is folded in the model of lowest free energy. PLMVd exhibits limited homologies with other viroids and some satellite RNAs, but it does not have any of the central conserved sequences characteristic of the subgroups of typical viroids. However, a segment of approximately one-third of the PLMVd sequence has the elements required to form in the RNAs of both polarities the hammerhead structures proposed to act in the in vitro self-cleavage of avocado sunblotch viroid (ASBVd) and some satellite RNAs. Plus and minus partial- and full-length RNA transcripts of PLMVd containing the hammerhead structures displayed self-cleavage during transcription and after purification as predicted by these structures. These data are consistent with the high stability of the PLMVd hammerhead structures, more similar to the corresponding structures of some satellite RNAs than to those of ASBVd, and indicate that the self-cleavage reactions of PLMVd are most probably mediated by single hammerhead structures. Our results support the inclusion of PLMVd in a viroid subgroup represented by ASBVd, whose members are characterized by their ability to self-cleave in vitro, and probably in vivo, through hammerhead structures. A consensus phylogenetic tree has been obtained suggesting that PLMVd, together with ASBVd, may represent an evolutionary link between viroids and viroid-like satellite RNAs.

Base Sequence↗