Abstract:
:One of the enduring problems in the study of social evolution has been to understand how cooperation can be maintained in the presence of freeloaders, individuals that take advantage of the more cooperative members of groups they are eager to join. The freeloader problem has been particularly troublesome when groups consist of nonrelatives, and no inclusive fitness benefits accrue to individuals that contribute more heavily to communal activities. These theoretical difficulties, however, are not mirrored by the numerous examples of cooperative or even altruistic behaviors exhibited by groups of nonrelatives in nature (e.g., many human groups, communally nesting bees, multiple queen-founding ants, cellular slime molds, and social bacteria). Using a model in which cooperation and grouping tendencies are modeled as coevolving dynamical variables, I show that the freeloader problem can be addressed when group-size effects on fitness are considered explicitly. I show that freeloaders, whose presence is reflected in the development of linkage disequilibrium between grouping and cooperation, increase in frequency when rare, but are selected against when common due to the reduced productivity of the groups they overburden with their presence. Freeloader frequencies thus periodically rise and fall around an equilibrium shown here to be dynamic. These results highlight the importance of group-level effects in the origin and maintenance of sociality, illustrate the dynamic nature of equilibria when multiple levels of selection are involved, and provide a solution to the freeloaders paradox.
journal_name
Proc Natl Acad Sci U S Aauthors
Avilés Ldoi
10.1073/pnas.212408299keywords:
subject
Has Abstractpub_date
2002-10-29 00:00:00pages
14268-73issue
22eissn
0027-8424issn
1091-6490pii
212408299journal_volume
99pub_type
杂志文章abstract::We have isolated several lines of rat embryo cells transformed by simian virus 40. All these lines are fully transformed with regard to saturation density and serum sensitivity, but they differ greatly in their anchorage dependence, as assayed by efficiency of plating in methyl cellulose suspension. This set of lines ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.71.12.4792
更新日期:1974-12-01 00:00:00
abstract::It has been proposed that the causative agent of scrapie represents a class of infectious particle that is devoid of nucleic acid and that an altered form of the endogenous prion protein (PrP) is the agent. However, it has been difficult to exclude the possibility that PrP purified from scrapie tissues might be contam...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.13.4657
更新日期:1988-07-01 00:00:00
abstract::During exercise, increased energy demands are met by increased glucose production that occurs simultaneously with the increased glucose uptake. We had previously observed that, during exercise, metabolic clearance rate of glucose (MCR) increases markedly in normal, but only marginally in poorly controlled diabetic dog...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.88.4.1296
更新日期:1991-02-15 00:00:00
abstract::Inhibin, a gonadal hormone capable of preferential suppression of pituitary follicle-stimulating hormone (FSH) secretion, has recently been purified. The major form of this protein is an alpha beta heterodimer encoded by two separate genes. In contrast to the FSH-suppressing action of the alpha beta heterodimer, the b...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.84.14.5082
更新日期:1987-07-01 00:00:00
abstract::Hypertonicity-induced binding of the transcription factor TonEBP/OREBP to its cognate DNA element, ORE/TonE, is associated with increased transcription of several osmotically regulated genes. Previously, it was found that hypertonicity rapidly causes nuclear translocation and phosphorylation of TonEBP/OREBP and, more ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.241637298
更新日期:2002-01-22 00:00:00
abstract::Cell variants resistant to the cytotoxic effect of mycophenolic acid, an inhibitor of IMP dehydrogenase (IMP:NAD+ oxidoreductase, EC 1.2.1.14), were selected by a one-step procedure from Chinese hamster V79 cells. The frequency of these variants was increased in a dose-dependent manner after treatment with the mutagen...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.78.5.3151
更新日期:1981-05-01 00:00:00
abstract::A human liver cDNA library was screened by colony hybridization with a bovine factor X cDNA probe. Three of the positive plasmids contained overlapping DNA that coded for most of human factor X mRNA. DNA sequence analysis of these three clones allowed the prediction of the complete amino acid sequence of plasma factor...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.82.11.3591
更新日期:1985-06-01 00:00:00
abstract::During the analysis of liver protein expression in the offspring of male mice irradiated with fission-spectrum neutrons, one offspring displayed a heritable 50% decrease in the abundance of two proteins. Homozygous mice lacking detectable quantities of these proteins were obtained through breeding. Characterization of...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.24.11338
更新日期:1994-11-22 00:00:00
abstract::Gyrate atrophy (GA), a recessive eye disease involving progressive loss of vision due to chorioretinal degeneration, is associated with a deficiency of the mitochondrial enzyme ornithine aminotransferase (OATase; ornithine-oxo-acid aminotransferase; L-ornithine:2-oxo-acid aminotransferase, EC 2.6.1.13) with consequent...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.85.11.3777
更新日期:1988-06-01 00:00:00
abstract::Through use of a synthetic oligonucleotide probe, human insulin-like growth factor I (IGF-I) cDNA clones were isolated from a liver library. Two types of cDNAs were defined by restriction enzyme analysis and DNA sequencing. Both encode IGF-I precursors of either 195 or 153 amino acids. The two predicted protein precur...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.1.77
更新日期:1986-01-01 00:00:00
abstract::Crithidia fasciculata cells were treated with a plasmid (pDK96) containing pBR322 sequences, a Leishmania tarentolae maxicircle autonomously replicating sequence, and the bacterial gene for aminoglycoside 3' phosphotransferase I inserted between the yeast alcohol dehydrogenase 1 promotor and terminator sequences. Resi...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.83.16.6058
更新日期:1986-08-01 00:00:00
abstract::Priming of the organ-specific premetastatic sites is thought to be an important yet incompletely understood step during metastasis. In this study, we show that the metastatic tumors we examined overexpress granulocyte-colony stimulating factor (G-CSF), which expands and mobilizes Ly6G+Ly6C+ granulocytes and facilitate...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1015855107
更新日期:2010-12-14 00:00:00
abstract::mAbs against tumor-associated carbohydrate antigens have the potential to play a prominent role in cancer immunotherapy. However, it has not been possible to fully exploit the clinical utility of such antibodies primarily, because those of adequate affinity could be derived only from murine sources. To address this pr...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.96.12.6953
更新日期:1999-06-08 00:00:00
abstract::A nuclear protein, termed leucine-rich acidic nuclear protein (LANP), has been isolated from among rat cerebellar proteins whose expression was transiently increased during an early stage of postnatal development. The amino acid sequence, deduced from its cDNA, showed that LANP contains 247 amino acids consisting of t...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.91.21.9670
更新日期:1994-10-11 00:00:00
abstract::We present a model describing how Mg(2+) binds and stabilizes specific RNA structures. In this model, RNA stabilization arises from two energetically distinct modes of Mg(2+) binding: diffuse- and site-binding. Diffusely bound Mg(2+) are electrostatically attracted to the strong anionic field around the RNA and are ac...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.221234598
更新日期:2001-10-23 00:00:00
abstract::Alternative ribosome subunit proteins are prevalent in the genomes of diverse bacterial species, but their functional significance is controversial. Attempts to study microbial ribosomal heterogeneity have mostly relied on comparing wild-type strains with mutants in which subunits have been deleted, but this approach ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.2009607117
更新日期:2020-08-11 00:00:00
abstract::While the general structure of immunoglobulin chains has remained relatively unchanged throughout evolution, the organization of the genes encoding these molecules differs substantially. To understand how the rearranging immunoglobulin system arose, it is necessary to examine living representatives of the most early v...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.21.9882
更新日期:1993-11-01 00:00:00
abstract::The nucleolinus is an RNA-rich compartment, closely apposed to or embedded within the nucleolus. Discovered over 150 y ago, fewer than two dozen articles have been published on the nucleolinus, probably because complex histochemical stains are required for its visualization in the great majority of cells. The nucleoli...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1008469107
更新日期:2010-08-03 00:00:00
abstract::A particularly promising approach to deconstructing and fractionating lignocellulosic biomass to produce green renewable fuels and high-value chemicals pretreats the biomass with organic solvents in aqueous solution. Here, neutron scattering and molecular-dynamics simulations reveal the temperature-dependent morpholog...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1922883117
更新日期:2020-07-21 00:00:00
abstract::The ability of cocaine to inhibit the dopamine transporter (DAT) appears to be crucial for its reinforcing properties. The potential use of drugs that produce long-lasting inhibition of the DAT as a mean of preventing the "high" and reducing drug-seeking behavior has become a major strategy in medication development. ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.19.10388
更新日期:1996-09-17 00:00:00
abstract::Lipoprotein oxidation is thought to play a pivotal role in atherogenesis, yet the underlying reaction mechanisms remain poorly understood. We have explored the possibility that high density lipoprotein (HDL) might be oxidized by peroxidase-generated tyrosyl radical. Exposure of HDL to L-tyrosine, H2O2, and horseradish...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.90.14.6631
更新日期:1993-07-15 00:00:00
abstract::Extracellular stimuli regulate neuronal differentiation and subtype specification during brain development, although the intracellular signaling pathways that mediate these processes remain largely unclear. We now show that the PDK1-Akt pathway regulates differentiation of telencephalic neural precursor cells (NPCs). ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.0808400106
更新日期:2009-08-04 00:00:00
abstract::Given a collection L of n points on a sphere [Formula: see text] of surface area n, a fair allocation is a partition of the sphere into n parts each of area 1, and each is associated with a distinct point of L. We show that, if the n points are chosen uniformly at random and if the partition is defined by a certain "g...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1720804115
更新日期:2018-09-25 00:00:00
abstract::Antinuclear autoantibodies (ANA) appeared in the plasma of lethally irradiated H-2d histocompatible DBA/2 and BALB/c mice several weeks after intravenous transplantation of 2 to 4 x 10(6) bone marrow cells from 3-week-old animals of the autoimmune New Zealand Black (NZB) strain. Little or no ANA development was observ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.71.6.2162
更新日期:1974-06-01 00:00:00
abstract::Tandem gene duplication is an important mutational process in evolutionary adaptation and human disease. Hypothetically, two tandem gene copies should produce twice the output of a single gene, but this expectation has not been rigorously investigated. Here, we show that tandem duplication often results in more than d...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1605886113
更新日期:2016-05-24 00:00:00
abstract::The efficacy of active immunization with the cocaine immunogen GNC-keyhole limpet hemocyanin (KLH) in preventing cocaine self-administration reinstatement was assessed in rats. An animal model of relapse was used where rats were trained to self-administer cocaine, subjected to a period of extinction by substituting th...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.97.11.6202
更新日期:2000-05-23 00:00:00
abstract::The seventh cholera pandemic caused by Vibrio cholerae O1 El Tor (ET) has been superseded in Asia and Africa by altered ET possessing the cholera toxin (CTX) gene of classical (CL) biotype. The CL biotype of V. cholerae was isolated, along with prototypic and altered ET, during the 1991 cholera epidemic in Mexico and ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1323408111
更新日期:2014-07-08 00:00:00
abstract::The chemical dynamics of lakes and streams affect their suitability as aquatic habitats and as water supplies for human needs. Because water quality is typically monitored only weekly or monthly, however, the higher-frequency dynamics of stream chemistry have remained largely invisible. To illuminate a wider spectrum ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.1304328110
更新日期:2013-07-23 00:00:00
abstract::The fifth exons of major histocompatibility complex (MHC) class I genes encode a transmembrane domain (TM) that is largely responsible for class I antigen cell-surface expression usually through conventional hydrophobic amino acid-membrane interactions or, less often, through phosphatidylinositol linkage. In this repo...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.88.11.4666
更新日期:1991-06-01 00:00:00
abstract::Mutations in the gene encoding the endothelin receptor type B (EDNRB) produce congenital aganglionic megacolon and pigment abnormalities in mice and humans. Here we report a naturally occurring null mutation of the EDNRB gene in spotting lethal (sl) rats, which exhibit aganglionic megacolon associated with white coat ...
journal_title:Proceedings of the National Academy of Sciences of the United States of America
pub_type: 杂志文章
doi:10.1073/pnas.93.2.867
更新日期:1996-01-23 00:00:00