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Results for “Evolutionary adaptability”

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PubMed2026

LitCTL1: A novel C-type lectin involved in the mucosal and cellular immunity of the common periwinkle Littorinalittorea.

C-type lectins (CTLs) are vital pattern-recognition receptors (PRRs) that mediate innate immune responses in mollusks, yet their characterization in Caenogastropoda, the largest gastropod group, remains limited. This study characterizes LitCTL1, a novel secreted single-domain C-type lectin from the common periwinkle, Littorina littorea. The 199-amino acid polypeptide contains a conserved carbohydrate recognition domain with canonical QPD and WND motifs and is predicted to form a homodimer. Uniquely, LitCTL1 was localized in both circulating hemocytes and mucus-secreting epithelial cells of the foot, mantle, and hypobranchial gland - the first report of such dual localization for a molluscan lectin, linking systemic and mucosal defense. Expression analysis revealed that LitCTL1 is constitutively expressed in hemocytes. Functional assays with recombinant LitCTL1 demonstrated its role as a potent opsonin with hemagglutinating activity, significantly enhancing hemocyte spreading and the phagocytosis of zymosan. Genomic analysis reveals that LitCTL1 belongs to a rapidly diversifying, genus-specific expansion distinct from conserved perlucin-like lineages. These results identify LitCTL1 as a key effector molecule in both systemic and mucosal innate immunity, likely reflecting an evolutionary adaptation to the microbial challenges of the intertidal environment.

Animals↗

PubMed1979

Release and distribution of [3H]norepinephrine in nonpigmented and pigmented rabbit iris.

Unequal accumulation of drugs in pigmented and nonpigmented iris has been known for some time. However, at low concentrations of the sympathetic neurotransmitter norepinephrine, the accumulation is equal in both types of irides. The spontaneous and potassium-induced release of 3H was studied in isolated rabbit irides labeled with 0.1 micron [3H]norepinephrine ([3H]NE). The spontaneous outflow and the tissue 3H content were similar in both types of irides, but the potassium-induced release was significantly higher in nonpigmented iris. When irides were labeled with [3H]NE in the presence of 1 micron desmethylimipramine, the potassium-induced release was still significantly higher in nonpigmented than in pigmented iris, although the tissue 3H content was higher in the latter. Subcellular distribution of [3H]NE in both types of irides is presented. The data indicate that [3H]NE is distributed unequally in both types of irides in spite of equal tissue accumulation. The binding of NE by the pigment cell suggests an additional site of loss, or site of uptake, of the transmitter in melanin-containing tissues. The physiological significance of such an unequal release in relation to the evolutionary adaptation of the eye to light is discussed.

Animals↗

PubMed2025

The genetic basis of chloride exclusion in grapevines.

Mediterranean regions are among the most important areas for global grape production, characterized by dry climates and frequent challenges associated with soil salinity. In these environments, chloride toxicity is a major factor limiting vine growth and fruit quality. Despite the critical role of chloride exclusion in salinity tolerance, the genetic mechanisms underlying this trait remain poorly understood. In this study, we analyzed natural variation in chloride exclusion using a diverse panel of 335 accessions representing 18 wild and cultivated Vitis species. This panel, comprising accessions from the southwestern United States and Mexico, captures a broad range of evolutionary adaptations to abiotic stress and provides a valuable genetic resource for breeding efforts aimed at introducing novel traits. Using genome-wide association and quantitative trait loci (QTL) mapping, we identified a major QTL on chromosome 8, now designated qClEx8.1, containing candidate genes encoding cation/H⁺ exchangers (CHXs), which are involved in ion transport and homeostasis. To validate these findings, we analyzed a mapping population derived from Vitis acerifolia longii 9018 and the commercial rootstock GRN3, confirming the chromosome 8 locus as a major determinant of chloride exclusion. Structural variant analysis revealed nonsynonymous substitutions within CHX genes that may influence protein function and salinity tolerance. Additionally, we discovered a novel QTL on chromosome 19 enriched with G-type lectin S-receptor-like serine/threonine-protein kinases, known regulators of stress signaling. By integrating phenotypic and genomic data across a diverse Vitis collection, this study advances our understanding of the genetic architecture underlying chloride exclusion and highlights candidate genes for breeding salt-tolerant rootstocks.

Vitis↗

PubMed2025

Evolutionary and Functional Analysis of Caspase-8 and ASC Interactions to Drive Lytic Cell Death, PANoptosis.

Caspases are evolutionarily conserved proteins essential for driving cell death in development and host defense. Caspase-8, a key member of the caspase family, is implicated in nonlytic apoptosis, as well as lytic forms of cell death. Recently, caspase-8 has been identified as an integral component of PANoptosomes, multiprotein complexes formed in response to innate immune sensor activation. Several innate immune sensors can nucleate caspase-8-containing PANoptosome complexes to drive inflammatory lytic cell death, PANoptosis. However, how the evolutionarily conserved and diverse functions of caspase-8 drive PANoptosis remains unclear. To address this, we performed evolutionary, sequence, structural, and functional analyses to decode caspase-8's complex-forming abilities and its interaction with the PANoptosome adaptor ASC. Our study distinguished distinct subgroups within the death domain superfamily based on their evolutionary and functional relationships, identified homotypic traits among subfamily members, and captured key events in caspase evolution. We also identified critical residues defining the heterotypic interaction between caspase-8's death effector domain and ASC's pyrin domain, validated through cross-species analyses, dynamic simulations, and in vitro experiments. Overall, our study elucidated recent evolutionary adaptations of caspase-8 that allowed it to interact with ASC, improving our understanding of critical molecular associations in PANoptosome complex formation and the underlying PANoptotic responses in host defense and inflammation. These findings have implications for understanding mammalian immune responses and developing new therapeutic strategies for inflammatory diseases.

Caspase 8↗

PubMed2025

A Functionally Conserved yet Dynamically Evolving Toolkit Underpinning Molluscan Biomineralization: Insights From Shell and Radula.

The molluscan shell and radula constitute pivotal molluscan innovations, each characterized by distinct functions and diverse forms, regulated by the highly specific biomineralization regulatory networks. Despite their paramount importance, the conserved components and adaptive evolutionary processes governing these regulatory networks remain unresolved. To address this knowledge gap, we advocate for the integration of data from less-explored lineages, such as Scaphopoda, as an essential step. This study presents the inaugural comprehensive transcriptome analysis of Pictodentalium vernedei, a representative species of Scaphopoda distinguished by a unique and evolutionarily conserved shell morphology and radula structure. Furthermore, comparative transcriptome/genome analyses are employed to unravel the conservatism and evolutionary innovation of the involved biomineralization regulatory elements. Our findings underscore the central role of secretomes in governing biomineralization processes, and we identified a fundamental set of 26 domains within molluscan secretomes, forming an essential functional protein domain repertoire necessary for the transformation of inorganic ions into biomineralized structures. This core biomineralization toolkit has undergone independent expansion and lineage-specific recruitment, giving rise to novel, modular domain architectures. This may be essential for the functional specialization and morphological diversification of shell and radula structures. These evolutionary processes are driven by the independent co-option of ancient genes and the emergence of novel de novo genes. This comprehensive investigation not only contributes insights into the evolution of molluscan biomineralization structures but also establishes avenues for further scholarly exploration.

Animals↗

PubMed1977

An anthropological perspective on the evolution and lateralization of the brain.

The purpose of this paper is to review the anthropological evidence relating to the cultural determinants of the right-hand first postaulted by Hertz in his classic study. Also a genetic/cultural conformity model of handedness is presented that postulates that the incidence of handedness in a society is held to result both from the genetic expression of handedness interacting with cultural pressures towards conformity. The evolutionary basis for the hemispheric functional organization into cognitive and perceptual hemispheric functions is discussed in terms of "right-handed dominant homozygotes, DD," "heterozygotes, DR," mixed-handers, and "left-handed recessive homozygotes, RR." The cross-cultural distribution of handedness provides support for this model since the more conforming agriculturalists as measured by the Asch Test have a significantly lower incidence of left-handedness (0.59%, 1.5% and 3.4%), while the more permissively socialized Eskimo and Arunta hunters, who are seen to be more independent on the Asch Test, have 11.3% and 10.5% left-handers, respectively. Also, due to the greater pressures for females to conform in agricultural societies, the incidence of female left-handedness in agricultural societies is 0% out of 330 female Ss, with 3.8%, 0.79%, and 2.5% in agricultural males, as contrasted with the Eskimo hunters who have 12.5% left-handed males and 10.3% left-handed females, showing no significant sex difference. A further Hong Kong-English study also supports the genetic/cultural conformity model with a significantly lower incidence of Hong Kong Chinese left-handers (RR: male = 2.7%, and female = 4.2%). The next section, concerned with the neonatal sex-hormone differentiation and lateralization processes, provides a neuropsychologic theory relating to spatial and linguistic skills that is relevant to the following section, which deals with relationships between laterality and cognitive style. The results are also presented for the Alaskan Eskimo in relation to hand, eye, auditory dominance and cognitive style. The analysis of Eskimo fixed-versus mixed-laterality data also confirms, as predicted, that both within and across a modality (e.g., right hand/right eye/right ear) fixed right-dominance Eskimo Ss are more field-independent than mixed-dominance Ss, while the fixed left-dominance Ss are the most field-dependent and have lower spatial skills. The discussion section reviews the papers relating to the genetic/conformity model of handedness, as well as laterality and cognitive style. The evolutionary adaptive significance of sex differences in gonadal differentiation and lateralization of the brain on spatial and linguistic skills are also reviewed. The conclusions are concerned with the implications for biosocial theory and the rapidly changing incidence of left-handedness due to accompanying changes in cultural pressures both within and across cultures.

Adult↗

PubMed2025

Myo-inositol is a key regulator of avian metabolism: From mechanisms to seasonal behavior.

Being naturally hyperglycemic and insulin insensitive, birds maintain plasma glucose levels twice as high as mammals of similar size. Recent evidence suggests that perturbation of myo-inositol (MI) plays a role in mammalian hyperglycemic regulation. Using an integrative approach, we identify a fundamental role of MI in avian metabolism. We show that MI transporters are highly conserved across birds and that dietary MI reduces fat accumulation in Anna's hummingbirds. MI consumption by hummingbirds varies with seasonal changes in body mass, consistent with a regulatory role. Furthermore, MI enhances fatty acid oxidation in avian cells, via effects on pyruvate-dehydrogenase complexes, indicating a role in mitochondrial fuel selection. Our findings underscore the importance of MI in avian metabolism, offering insights into their evolutionary adaptations in the context of insulin insensitivity.

Animals↗

PubMed1978

Parasite-specified phagocytosis of Chlamydia psittaci and Chlamydia trachomatis by L and HeLa cells.

Phagocytosis of the 6BC strain of Chlamydia psittaci and the lymphogranuloma venereum 440L strain of Chlamydia trachomatis by L cells and HeLa 229 cells occurred at rates and to extents that were 10 to 100 times greater than those observed for the phagocytosis of Escherichia coli and polystyrene latex spheres. Both species of Chlamydia were efficiently taken up by host cells of a type they had not previously encountered. Phagocytosis of chlamydiae was brought about by the interaction of parasite surface ligands with elements of the host cell surface. The chlamydial ligands were readily denatured by heat, were masked by antibody, and were resistant to proteases and detergents. The host cell components were reversibly removed by proteases. Chlamydial phagocytosis was inhibited when host cells were incubated for many hours with cycloheximide. It was suggested that the presence on the chlamydial cell surface of ligands with high affinity for normal, ubiquitously occurring structures on the surface of host cells is an evolutionary adaptation to intracellular existence. The term parasite-specified phagocytosis was used to describe the efficient phagocytosis of chlamydiae by nonprofessional phagocytes and to distinguish it from the host-specified immunological and non-immunological phagocytosis carried out by professional phagocytes.

Chlamydia trachomatis↗

PubMed2026

TALEs, TALENs, and TALE Base Editors: From Plant Pathology to Biotechnology.

TALEs (transcription activator-like effectors) are an excellent example of how studying pathogen-host interactions can lead to significant biotechnology inventions. TALEs are bacterial effectors that are translocated into plant cells via a bacterial type III secretion system. Once inside the host cell, they are imported into the nucleus to bind specific promoters and induce expression of target genes, thereby supporting the bacterial infection. TALEs are found throughout many, but not all, Xanthomonas pathovars, which can be severe pathogens of different crops. The key feature of TALEs is their modular DNA-binding domain, which allows a simple evolutionary adaptation to novel DNA sequences as well as simple cloning of designer TALEs with desired DNA-binding specificity. Accordingly, TALE nucleases started the genome-editing revolution, and TALE base editors are the latest tools to efficiently edit chloroplast and mitochondrial genomes. We review recent advances in Xanthomonas genomics, synthesize current knowledge about naturally occurring TALEs, and highlight current roles of TALEs in genome editing and synthetic biology.

Xanthomonas↗

PubMed2026

In silico analysis and comparison of the metabolic capabilities of different organisms by reducing metabolic complexity.

BACKGROUND: Understanding how metabolic capabilities diverge across microbial species is essential for deciphering community function, ecological interactions, and the design of synthetic microbiomes. Despite shared core pathways, microbial phenotypes can differ markedly due to evolutionary adaptations and metabolic specialization. Genome-scale metabolic models (GEMs) provide a systems-level framework to explore these differences; however, their complexity hinders direct comparison. RESULTS: We introduce NIS (Neidhardt-Ingraham-Schaechter), a computational workflow that integrates the redGEM, lumpGEM, and redGEMX algorithms to systematically reduce genome-scale models into biologically interpretable modules. This approach enables direct, quantitative comparison of fueling pathways, biomass biosynthetic routes, and environmental exchange processes while retaining essential metabolic information. We first demonstrate the utility of NIS by analyzing Escherichia coli and Saccharomyces cerevisiae, which revealed both conserved and divergent strategies in central metabolism, biosynthetic cost, and substrate utilization. We then applied NIS to the core honeybee gut microbiome, uncovering distinct metabolic traits, functional redundancy, and complementarity that help explain auxotrophy, cross-feeding interactions, and microbial coexistence. CONCLUSIONS: NIS provides an automated, scalable, and reproducible framework for dissecting microbial metabolic networks beyond gene content or taxonomy. By linking metabolism to ecological function, NIS offers new opportunities to interpret microbial community dynamics and to support the rational design of microbiomes in health, agriculture, and environmental applications. Video Abstract.

Metabolic Networks and Pathways↗

PubMed2025

Functional genomics of trypanotolerant and trypanosusceptible cattle infected with Trypanosoma congolense across multiple time points and tissues.

Human African trypanosomiasis (HAT), or sleeping sickness, is a neglected tropical disease caused by infection with trypanosome parasites (Trypanosoma spp.). These are transmitted by infected tsetse flies (Glossina spp.) and cause a similar disease in animals, known as African animal trypanosomosis (AAT), which is one of the largest constraints to livestock production in sub-Saharan Africa and causes a financial burden of approximately $4.5 billion annually. Some African Bos taurus cattle populations have an important evolutionary adaptation known as trypanotolerance, a genetically determined tolerance of infection by trypanosome parasites (Trypanosoma spp.). Trypanotolerant African B. taurus N'Dama and trypanosusceptible Bos indicus Boran cattle responded in largely similar ways during trypanosome infection when gene expression was examined using blood, liver, lymph node, and spleen samples with peaks and troughs of gene expression differences following the cyclic pattern of parasitaemia exhibited during trypanosome infection. However, differences in response to infection between the two breeds were reflected in differential expression of genes related to the immune system such as those encoding antimicrobial peptides and cytokines, including, for example, the antimicrobial peptide encoding genes LEAP2, CATHL3, DEFB4A, and S100A7 and the cytokine genes CCL20, CXCL11, CXCL13, CXCL16, CXCL17, IL33, and TNFSF13B. In addition, transcriptional profiling of peripheral blood identified expression differences in genes relating to coagulation and iron homeostasis, which supports the hypothesis that the dual control of parasitaemia and the anaemia resulting from the innate immune response to trypanosome parasites is key to trypanotolerance and provide new insights into the molecular mechanisms underlying this phenomenon.

Animals↗

PubMed2026

RND-mediated efflux couples antimicrobial resistance and hypervirulence in contemporary Vibrio cholerae.

The prevailing view in bacterial pathogenesis is that antimicrobial resistance and virulence are constrained by evolutionary trade-offs, with resistance mechanisms imposing fitness costs that attenuate pathogenic potential. Herein we document that contemporary Vibrio cholerae clinical isolates from the ongoing seventh pandemic have circumvented this paradigm by coupling multidrug resistance with hypervirulence. We examined five geographically diverse Wave 3 isolates collected between 2017 and 2019 and compared them to early pandemic strains. These contemporary isolates exhibited both broad-spectrum antimicrobial resistance and markedly enhanced colonization capacity in the infant mouse model. Phylogenetic analysis of 67 O1 El Tor genomes spanning 1960-2019 confirmed that the isolates cluster within a representative Wave 3 sublineage. We identified the VexB RND efflux pump as a mediator of this coupled phenotype. Elevated vexB expression in the contemporary isolates conferred resistance to multiple antibiotic classes, while vexB inactivation simultaneously impaired resistance and colonization. This dual function was not observed in early pandemic strains, consistent with a recent evolutionary adaptation. VexB-mediated hypervirulence occurred through multiple pathways independent of cholera toxin and toxin-coregulated pilus production levels. VexB deletion impaired bacterial adherence to intestinal epithelial cells, impaired motility, and increased susceptibility to membrane-active antimicrobials. In contrast, laboratory evolution under antibiotic pressure alone generated resistant but avirulent strains, demonstrating that complex selective forces in nature enabled the co-optimization of resistance and virulence. These findings establish VexB as a molecular link between antimicrobial resistance and hypervirulence in pandemic V. cholerae, highlighting efflux pumps as dual-function therapeutic targets whose inhibition could both restore antibiotic activity and attenuate disease.

Animals↗

PubMed2025

Comparative Genomic Analysis of Six Mycoplasma Gallisepticum Strains: Insights into Genetic Diversity and Antibiotic Resistance.

Mycoplasma gallisepticum (MG) is a significant pathogen that causes respiratory diseases, which have had a substantial economic impact on the poultry industry. Despite the resistance of MG to antibiotics, it is imperative to identify genetic diversity in order to develop countermeasures. In this study, the genomes of six MG strains were examined to gain deeper insights into the mutations. The data pertaining to Variant Annotation and Mutation Analysis using SnpEff, along with the calculation of mutation rates as the ratio of total mutations to the length of the genomic regions analyzed, were thoroughly examined. The comprehensive evaluation yielded a total of 25,942 variants across the six strains, underscoring substantial genetic diversity. Notably, strain S6 exhibited a preponderance of frameshift mutations. A notable finding was the presence of a mutation in the MsbA gene shared by all six strains. Furthermore, five of the six strains, with the exception of strain F99 Lab, exhibited a mutation at position 5158, which impacts a multidrug transport system. Notably, strain ATCC exhibits a distinctive mutation at position 942, while strain S6 displays a unique mutation at position 6855, which is linked to efflux ABC transporter components. Furthermore, a substantial degree of genetic variation was observed among the CrmA, GapA, and vlhA genes among the various strains. High-impact changes, such as insertions and deletions, exhibited a higher frequency in CrmA, particularly in strain S6. Conversely, nonsynonymous variations demonstrated a heightened prevalence in GapA, particularly in strain F99 Lab. The vlhA gene exhibited a spectrum of effects, ranging from synonymous mutations to high-impact mutations such as stop-gains and frameshifts, particularly in strains k5111a and k4602. The functional variations observed among the strains can be attributed to these mutations, which have the potential to alter gene expression or protein function. Furthermore, substantial mutations in the dxr and rpoC genes were associated with antibiotic resistance. These mutations underscore the ongoing evolutionary adaptations of M. gallisepticum. Consequently, there is an imperative for the revision of treatment protocols and the formulation of targeted vaccines to regulate resistance within the poultry industry.

Mycoplasma gallisepticum↗

PubMed2026

Evolutionary patterns and repeated adaptive strategies of deep-sea anemones.

Sea anemones occupy the full depth range of the oceans, yet their evolutionary patterns and adaptive strategies to the enigmatic deep sea have remained contentious and poorly resolved. Here, we assemble genomes (n = 13) and transcriptomes for 15 species collected between 432 and 6,000 m and integrate them with publicly available actiniarian data. We find support for a shallow-water origin of Actiniaria through a framework that emphasizes genome-scale changes associated with habitat transitions. Most strikingly, these changes include repeated dismantling of the circadian toolkit across deep-sea lineages. In addition to convergent gene losses in photo- and temperature-regulatory genes, we find that some deep-sea lineages have experienced recurrent loss or pseudogenization of key meiotic genes (e.g., Meiosin, Ythdc2, Spo11, and Mlh3), suggesting reduced meiotic capacity in some lineages. Despite this extensive genomic erosion, deep-sea anemones exhibit molecular tuning: specific amino acid substitutions improve enzyme performance under low-temperature conditions relevant to the deep sea, while selective expansions of gene families related to neural excitability, membrane systems, and other functions may help maintain physiological performance in this environment. Functional assays in yeast indicate enhanced performance of the deep-sea variants at 4°C. These results define a "loss-optimization-innovation" triad that underlies bathymetric adaptations and may apply to other deep-sea fauna worldwide.

Actiniaria↗

PubMed2026

Complete telomere-to-telomere genome assembly of Guazuma ulmifolia uncovers evolutionary mechanisms, drought adaptation, and flavonoid biosynthesis.

The first T2T reference genome of Guazuma ulmifolia is reported, which serves as a core genomic resource for stress adaptation research and stress-tolerant breeding in cacao wild relatives. Climate change, particularly increased incidence of drought, poses a major threat to food security. Understanding the genomic basis of environmental adaptation in crop wild relatives can provide valuable resources for improving stress resilience. Guazuma ulmifolia, a wild relative of Theobroma cacao with important ecological and medicinal value, lacks high-quality reference genomic resources. Here, we report the first telomere-to-telomere (T2T) chromosome-level genome assembly of G. ulmifolia, with a genome size of 311.31 Mb, contig N50 of 35.19 Mb, and 98.70% BUSCO completeness. Repetitive sequences constitute 27.43% of the G. ulmifolia genome, with LTR retrotransposons as the predominant class. Comparative genomic analyses revealed that genome-size variation among Malvaceae species is associated with differences in polyploidization history and TE dynamics. Ancestral karyotype reconstruction identified five lineage-specific chromosome fusion events distinguishing G. ulmifolia from T. cacao. Comparative analyses further identified tandem duplication-associated expansion of stress-related LEA and GST gene families, suggesting potential genomic features associated with stress responses. Flavonoid biosynthesis genes were largely conserved in copy number but showed tissue-specific expression patterns, providing candidate genes for investigating secondary metabolism. Together, this study establishes a high-quality T2T genome resource for exploring genome evolution, chromosome organization, and stress-related genomic features in Malvaceae.

Genome, Plant↗

PubMed1976

Do evolutionary changes in cytochrome c structure reflect functional adaptations?

Following the demonstration that the rate of evolutionary change in the amino acid sequences of cytochromes c of eukaryotic species was not constant either for a single line of phylogenetic descent during different evolutionary intervals or for separate lines of descent, the concept that neutral mutations account for the vast majority of the evolutionary variations could no longer be accepted. Previous studies had shown that all eukaryotic cytochromes c tested appeared to be functionally indistinguishable in their reaction with mitochondrial respiratory chain components. However, an examination of the kinetics at low ionic strength led to the discovery of a high affinity reaction of cytochrome c with cytochrome c oxidase that revealed large differences in activity between the cytochromes of the horse, baker's yeast and the protist Euglena. Observed Km values for this reaction of 10(-7) to 10(-8) M appear to represent actual dissociation constants, as demonstrated by direct binding studies of cytochrome c with purified cytochrome c oxidase. The high affinity reaction is sensitive to ionic strength and inhibited by ADP and ATP in the range of physiological concentrations, ATP being three times as effective as ADP. The possibility is discussed that this effect of ATP on cytochrome c binding to its oxidase could provide the basis of a mechanism for mitochondrial respiratory control. The demonstration of differences between cytochrome c of various species in this kinetic system opens the way to a systematic study of the possible evolutionary adaptations of cytochromes c to their oxidases.

Amino Acid Sequence↗

PubMed2026

Tandem duplication-driven expansion and UV-B stress adaptation of the LHC gene family in Artemisia annua L.

BACKGROUND: Artemisia annua L., is the primary natural source of the antimalarial drug artemisinin. In nature, fluctuating light is a major environmental stress that affects plant growth and artemisinin biosynthesis. Although the light-harvesting chlorophyll a/b-binding (LHC) superfamily plays a key role in mediating plant responses to fluctuating light, systematic research of this gene family in A. annua has not yet been conducted, limiting our understanding of light adaptation in this medicinally important species. RESULTS: This study investigated the evolutionary dynamics and functional adaptation of the light-harvesting chlorophyll a/b-binding (LHC) superfamily in A. annua, with a focus on the early light‑induced protein (ELIP) subfamily. Comparative genomics of 24 plant species showed that the LHC superfamily recently expanded in the examined Asteraceae lineages through duplication events. In A. annua, 229 LHC genes identified from four haplotype genomes comprised 205 allelic and 24 haplotype-specific loci, with the ELIP subfamily expanding significantly via tandem duplication. Notably, compared to non-Asteraceae plants, ELIPs exhibited a uniform single-exon architecture, indicating it is a genomic feature unique to Asteraceae plants. Population genomics of 41 individuals showed dynamic copy number variations ranging from 1 to 4 copies per locus. Interestingly, a structurally disrupted ELIP allele remained transcriptionally active and produced long aberrant transcripts, showing that this subfamily is still actively evolving. Under UV-B stress, AaELIP loci showed synchronized induction trend but differed in expression levels, suggesting a division into major and auxiliary roles within the expanded tandem cluster. Overall, while the response of ELIPs to light stress is evolutionarily conserved, this dramatic expansion and structural streamlining of AaELIPs may represent a key evolutionary adaptation that enhances the plant's ability to cope with intense light and radiation stress. CONCLUSIONS: Collectively, this study demonstrates a significant expansion of the LHC superfamily in A. annua, especially within the ELIP subfamily, as well as its robust response to UV-B treatment, underscoring the essential role of ELIPs in mediating light stress responses. These findings provide a valuable foundation for future research to uncover the molecular mechanisms underlying A. annua's adaptation to complex light environments.

Artemisia annua↗

PubMed2026

Comparative analysis of olfactory receptor repertoires reveals evolutionary dynamics and high-altitude adaptation in Schizopygopsis younghusbandi based on the chromosome-level genomes.

The olfactory receptor (OR) gene represent a significant multigene family in vertebrates, forming the core molecular basis of olfactory perception and playing a crucial role in the environmental adaptation of species. High-altitude ecosystems represent extreme habitats characterized by specific abiotic stresses, including low oxygen levels, low temperatures, and intense ultraviolet radiation. These environments also exhibit low aquatic biodiversity and a limited variety of odor molecules, factors that have influenced the adaptive evolution of the sensory systems in endemic species. However, the genetic mechanisms underlying olfactory adaptation in high-altitude freshwater fish remained inadequately understood. In this study, we performed comparative genomics analyses to reveal the evolutionary processes underlying the adaptive and functional evolution of OR genes in S. younghusbandi, a cyprinid fish endemic to the Qinghai-Xizang Plateau. The results indicated that, compared to their low-altitude relatives, S. younghusbandi possessed a significantly smaller number of OR genes, with only 98 genes, which revealed the contraction of the gene family. Phylogenetic analysis revealed that the OR genes of cyprinid fish could be categorized into two major lineages: type I and type II. The η and δ families, which perceive water-soluble odors, in S. younghusbandi underwent significant and specific expansion, while the ε family was completely absent. This pattern reflected adaptive changes in olfactory recognition to accommodate the simplified odor spectrum of high-altitude water bodies. Chromosomal localization analysis demonstrated that OR genes were clustered, and collinearity analysis confirmed the presence of conserved genomic fragments among species. Selection pressure analysis revealed that the Ka/Ks values of all homologous gene pairs were less than 1, indicating that the OR genes of S. younghusbandi underwent strong purifying selection as a group to preserve core olfactory function. A few genes exhibited relaxed selection characteristics, which may have facilitated the fine-tuning of adaptability to high-altitude environments. In conclusion, this study elucidated the evolutionary dynamics and adaptive characteristics of the OR gene in S. younghusbandi, offering a new perspective on the molecular mechanisms underlying olfactory adaptation at high altitudes and enriching the research on sensory evolution in vertebrates.

Schizopygopsis younghusbandi↗