PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “coevolution”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 37 records · Page 2Linked to original sources
PubMed2026

Genetic and environmental interactions outweigh mitonuclear coevolution for complex traits in Drosophila.

The interdependent relationship between mitochondrial and nuclear genomes is a powerful model for understanding how epistasis shapes the architecture and evolution of complex traits. Once considered a neutral marker, mitochondrial DNA variation is now recognized as critical to phenotypic evolution because of its epistatic interactions and history of coevolution with the nuclear genome. A central challenge in evolutionary genetics is to quantify the relative importance of stabilizing and directional selection shaping complex trait distributions within and among species. Both can act on interacting and/or co-evolving genes contributing to quantitative traits, but resolving their relative roles is complicated by the complex architecture of most traits. Here, we use a panel of 90 Drosophila mitonuclear genotypes to quantify the relative contributions of mitochondrial, nuclear, and environmental variation and their interactions to four metabolically demanding complex traits. We sample both within-species and between-species mitochondrial variation and observe stronger interaction effects attributable to within-species variation, consistent with stabilizing selection maintaining mitonuclear function. Additionally, culturing the flies on a mitochondrial Complex I inhibitor, rotenone, reveals significant genotype x environment (G×E and G×G×E) interaction effects, providing insight into how genetic variation can be maintained across changing environments. Our results have broader implications in medicine, where mitochondrial DNA donors with longer purifying selection histories may be safer for mitochondrial replacement therapies.

Journal Article↗
PubMed1991

Coevolution of self-fertilization and inbreeding depression. I. Mutation-selection balance at one and two loci.

Simple theories for the evolution of breeding systems suggest that the fate of an allele that modifies the rate of self-fertilization hinges only on the degree to which selfing reduces opportunities for outcrossing ("pollen discounting") and the extent of inbreeding depression. These theories predict that outcrossing evolves whenever deleterious mutations have a more severe effect in combination than expected from their individual effects. We study the evolutionary dynamics of a modifier of the rate of self-fertilization in populations subject to complete pollen discounting and recurrent mutations which impair viability at a single locus in diploids and at two loci in haploids. Our analysis indicates that genetic associations arising immediately upon the introduction of a rare modifier allele generate substantial quantitative and qualitative departures from expectation. Higher rates of segregation under selfing in our one-locus diploid model generate positive associations between enhancers of selfing and wild-type viability alleles, which in turn favor the evolution of selfing under a wider range of conditions than expected. Greater opportunities for recombination under outcrossing in our two-locus haploid model generate positive associations between enhancers of outcrossing and wild-type viability alleles. These associations favor the evolution of outcrossing under a wider range of conditions, and introduce the possibility of stable mixed mating systems involving both selfing and outcrossing. Our explicit analysis of genetic associations between loci affecting viability and the rate of self-fertilization indicates that modifiers that enhance the production of offspring with very high (and very low) viability by promoting segregation or recombination develop positive associations with high viability. This advantage of producing extremes can compensate for an initial disadvantage in offspring number.

Alleles↗
PubMed1991

Coevolution of self-fertilization and inbreeding depression. III. Homozygous lethal mutations at multiple loci.

We study the evolution of the rate of self-fertilization in response to deleterious mutations at multiple loci. Although partial selfing induces associations among loci even in the absence of linkage, associations among mutations at different loci are of a smaller order of magnitude than the mutation rate. Genotypes that carry homozygous lethal mutations in heterozygous form at i loci occur in frequencies of the order (Ti) mu i, in which T denotes the number of viability loci and mu the mutation rate. While associations between mutations at different loci remain small even under inbreeding, each viability locus develops an association with the modifier of the rate of self-fertilization that substantially affects the evolution of the breeding system. Positive associations between enhancers of selfing and haplotypes carrying multiple wild-type alleles and positive associations in heterozygosity between the modifier locus and the viability loci promote evolutionary increases in the rate of self-fertilization.

Biometry↗
PubMed1992

Coevolution of cytokine receptor families in the immune and nervous systems.

Close relationships between the nervous system and immune systems at molecular levels have now become evident. Receptors for CDF/LIF and CNTF, i.e., factors which play important roles in the nervous system, share a close structural similarity to those for IL-6, which is a molecule acting in the immune system. Receptors for these three factors belong to a subtype of cytokine receptor family (class IB cytokine receptor). We have constructed a higher subdomain structure of the receptor for CDF/LIF based on its known primary structures. The receptor contains immunoglobulin and fibronectin-like domains, in addition to common domains of the cytokine receptor, similar to those cell surface molecules of the neural immunoglobulin gene super family. These domains appear to have similar structures to the immunoglobulin. These lines of evidence suggest that the class IB cytokine receptor was formed as a result of those fusion of the genes for a more primitive cytokine receptor IA and for the neural immunoglobulin super gene family, and that, likewise, many molecules regulating neural development and those which act in the immune system have a common evolutionary origin.

Amino Acid Sequence↗
PubMed1992

Gene-culture coevolution: toward a general theory of vertical transmission.

A general formulation of cultural and genetic transmission is developed. The cultural transmission is vertical and the genetics may involve multiple loci. Each individual is represented by a phenogenotype, and conditions are given under which the evolutionary dynamics of phenogenotype frequencies are reducible to phenogametic or phenoallelic frequencies. The interaction between genes and culture is specified by an association measure, and results on the order of magnitude of this association at equilibrium are presented.

Biological Evolution↗
PubMed1992

Coevolution of the vertebrate integrin alpha- and beta-chain genes.

The integrin receptors are heterodimers whose alpha and beta subunits are encoded by separate, evolutionarily unrelated multigene families. Phylogenetic analysis of DNA sequences from these two gene families showed that they have not always evolved in a parallel fashion. The integrin alpha chains that can form heterodimers with beta 1 do not constitute a monophyletic group, nor do the beta chains which can form heterodimers with alpha V. On the other hand, the vertebrate alpha chains associating with beta 2 are a monophyletic group. In the metal cation-binding region of the alpha chain, an exon exchange took place between human alpha M and alpha X approximately 40-50 Mya, homogenizing this functionally important region in these two alpha chains. When integrin beta chains of different functional classes are compared, nonsynonymous (amino acid altering) nucleotide substitutions that alter amino acid residue charge in the central region of the molecule occur at a rate significantly higher than that expected under random replacement. By contrast, when closely related beta 1 chains are compared, residue charge is conserved in this region. These results pinpoint the central region as a focus of functional divergence among integrin beta chains, perhaps relating to the ability of each beta integrin class to associate with a specific array of alpha integrins. Furthermore, they imply that positive, directional selection on this region has occurred in the evolution of the integrin beta-chain gene family.

Animals↗
PubMed1977

Blood corpuscles and blood hemoglobins: a possible example of coevolution.

A model which equates oxygen transport to hemoglobin concentration and molecular weight is used to demonstrate that high concentrations of hemoglobin will augment oxygen transport only if the molecular weight of the hemoglobin is low. The evolution of corpuscles is a necessary counterpart to having high concentrations of the low molecular weight hemoglobins. corpuscles prevent loss of the small molecules by way of excretory filters and prevent the development of exceedingly high plasma osmotic pressures.

Biological Evolution↗
PubMed1975

Coevolution of a virus-alga system.

Plectonema boryanum, a filamentous blue-green alga, was cloned and then allowed to reach a steady state in a quasi-continuous culture in the presence of the algal virus, LPP-1. The culture was maintained for 3.5-month period during which time at least four distinct culture lysings were evident. After the fourth lysis the culture reached a steady-state level which was identical in its algal concentration to the preinfection level. Upon testing the characteristics of the evolved alga and virus variants, the following was determined: cell variants resistant to both the original virus and the derived virus had evolved, and there was no evidence of lysogeny present amony these cells. The evolved virus strains still grew on the parental algal strain, though with altered plaque morphology. Furthermore, they were antigenically similar to the parental virus, and showed no significant difference in adsorption rate or growth characteristics on parental cells. However, a low-grade chronic viral infection persisted in the culture. Rapid re-establishment of a dense, stable culture is apparantly the normal laboratory response of a procaryotic cell-virus system.

Adsorption↗
PubMed1992

Molecular variants of human papillomavirus type 16 from four continents suggest ancient pandemic spread of the virus and its coevolution with humankind.

We have amplified by the polymerase chain reaction, cloned, and sequenced genomic segments of 118 human papillomavirus type 16 (HPV-16) isolates from 76 cervical biopsy, 14 cervical smear, 3 vulval biopsy, 2 penile biopsy, 2 anal biopsy, and 1 vaginal biopsy sample and two cell lines. The specimens were taken from patients in four countries--Singapore, Brazil, Tanzania, and Germany. The sequence of a 364-bp fragment of the long control region of the virus revealed 38 variants, most of which differed by one or several point mutations. Phylogenetic trees were constructed by distance matrix methods and a transformation series approach. The trees based on the long control region were supported by another set based on the complete E5 protein-coding region. Both sets had two main branches. Nearly all of the variants from Tanzania were assigned to one (African) branch, and all of the German and most of the Singaporean variants were assigned to the other (Eurasian) branch. While some German and Singaporean variants were identical, each group also contained variants that formed unique branches. In contrast to the group-internal homogeneity of the Singaporean, German, and Tanzanian variants, the Brazilian variants were clearly divided between the two branches. Exceptions to this were the seven Singaporean isolates with mutational patterns typical of the Tanzanian isolates. The data suggest that HPV-16 evolved separately for a long period in Africa and Eurasia. Representatives of both branches may have been transferred to Brazil via past colonial immigration. The comparable efficiencies of transfer of the African and the Eurasian variants to the New World suggest pandemic spread of HPV-16 in past centuries. Representatives of the African branch were possibly transferred to the Far East along old Arab and Indonesian sailing routes. Our data also support the view that HPV-16 is a well-defined virus type, since the variants show only a maximal genomic divergence of about 5%. The small amount of divergence in any one geographic location and the lack of marked divergence between the Tanzanian and Brazilian African genome variants two centuries after their likely introduction into the New World suggest a very slow rate of viral evolution. The phylogenetic tree therefore probably represents a minimum of several centuries of evolution, if not an age equal to that of the respective human races.

Base Sequence↗
PubMed1992

Coevolution of hosts and microorganisms: an analysis of the involvement of cytokines in host-parasite interactions.

Parasites may employ particular strategies of eluding an immune response by taking advantage of those mechanisms that normally guarantee immunological self-tolerance. Much in the way as it occurs during the establishment of self-tolerance, live pathogens may induce clonal deletion, functional inactivation (anergy) and immunosuppression. At this latter level, it appears that certain pathogens produce immunosuppressive cytokine-like mediators or provoke the host to secrete cytokines that will compromise the anti-parasite immune response. It appears that immune responses that preferentially involve T helper 1 cells (secretors of interleukin-2-and interferon-gamma) tend to be protective, whereas T helper 2 cells (secretors of IL-4, IL-5, IL-6, and IL-10), a population that antagonizes T helper cells, mediate disease susceptibility and are involved in immunopathological reactions. Cytokines produced by T helper 2 cells mediate many symptoms of infection, including eosinophilia, mastocytosis, hyperimmunoglobulinemia, and elevated IgE levels. Administration of IL-2 and IFN-gamma has beneficial effects in many infections mediated by viruses, bacteria, and protozoa. The use of live vaccinia virus might be an avenue for the treatment of or the vaccination against infection. We have found that a vaccinia virus expressing the gene for human IL-2, though attenuated, precipitates autoimmune disease in immunodeficient, athymic mice. Thus, although T helper 1 cytokines may have desired immunostimulatory properties, they also may lead to unwarranted autoaggressive responses.

Animals↗
PubMed1990

Examination of protein sequence homologies. VII. The complementary molecular coevolution of ribosomal proteins equivalent to Escherichia coli L7/L12 and L10.

Recently reported P1, P2 and metabacteria line sequences of transposition-type 'A' proteins, equivalent to Escherichia coli ribosomal protein L7/L12, were examined using a correlation method which evaluates the sequence similarity quantitatively. As the sequences could be aligned along the alignment previously constructed for 25 various 'A' proteins, the inclusive alignment further supports the previous claims concerning the rule of "preservation units" and the transpositional regeneration for metabacterial and eukaryotic 'A' proteins. Yeasts contain multispecies of P1 and P2 line genes and their P1 line sequences show low correlation coefficient values compared to other P1 line sequences, indicating a great evolutionary distance between lower and higher eukaryotes. Five sequences of protein P0 from metabacteria, yeast, and human, of which about 20 residues at the C termini are homologous with those of their own transposition-type 'A' proteins, were similarly examined. The N-terminal three-quarters of the sequences align naturally and the first two-thirds of the alignment could involve the E. coli L10 (EL10) sequence. An alignment of the remaining sequences at the C termini was established, relying on the well-matching sequence similarities between the metabacteria 'A' protein and their P0 protein sequences. Finally, the C-terminal halves of P0 protein sequences corresponded with almost overall sequences of the transposition-type 'A' proteins. The gene fusion of a protein might have resulted in the formation of the P0 proteins. A coupling of this gene fusion and the transposition of prototype 'A' proteins may have given rise to the complementary molecular transformations required for the development toward higher organism cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed2026

Disruption of mitonuclear coadaptation and compensatory evolution after an extreme dietary shift in carnivorous butterflies.

Mitochondrial function depends on tight coordination between mitochondrial and nuclear genomes, which requires long-term coevolution to maintain mitonuclear coadaptation. While mitonuclear incompatibility is typically studied in the context of hybridization, other evolutionary scenarios that may disrupt coadaptation between the two genomes remain less explored. Here, we propose that extreme ecological niche shifts may disrupt mitonuclear coadaptation, which we test in carnivorous Miletinae butterflies with an extreme dietary transition. By generating high-quality genome assemblies, we found that Miletinae exhibit extensive chromosomal rearrangements. Comparative phylogenomic analyses revealed a striking asymmetric mitonuclear evolutionary response: Miletinae exhibit elevated mitochondrial nucleotide substitution rates compared to phytophagous relatives, whereas nuclear rates remain stable. This shift reverses the typical lepidopteran pattern where nuclear rates exceed mitochondrial rates. Interestingly, this mitochondrial acceleration is driven primarily by relaxed purifying selection rather than positive selection. To sustain mitochondrial function, the nuclear genome of Miletinae underwent pervasive, multilayered compensatory evolution. We detected strong signatures of positive selection and accelerated evolution in nuclear genes directly interacting with mitochondrial components across oxidative phosphorylation (OXPHOS) complexes, the mitochondrial translation, and replication and transcription machinery. Furthermore, this nuclear compensatory response extends to systems governing mitochondrial homeostasis, including protein quality control and RNA degradation and stabilization. Our results support a model in which extreme ecological transitions can disrupt ancestral mitonuclear coadaptation and promote the emergence of a new coadapted state through systemic nuclear compensation. This study broadens the conceptual framework of mitonuclear coevolution and highlights its role in facilitating evolutionary persistence after major ecological shifts.

Animals↗