A Gene for an Extended Phenotype

Hoover, Kelli; Grove, Michael; Gardner, Matthew R.; Hughes, David; McNeil, James; Slavicek, James M.

doi:10.1126/science.1209199

Cited by 203 publications

(242 citation statements)

References 12 publications

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“…It might be no coincidence that T. gondii triggers the synthesis of signaling compounds in its host, rather than producing these compounds itself (Gaskell et al, 2009;Prandovszky et al, 2011;Lim et al, 2013). Viruses depend completely on the metabolism of their host and, thus, should gain most when they manipulate the reallocation of host compounds, or the activity of existing signaling molecules, rather than inducing costly de-novo synthesis (Hoover et al, 2011). Second, DNA itself has a metabolic cost, and viruses and intracellular bacteria in particular are under high selective pressure to reduce their genome sizes to a minimum.…”

Section: Why Don't All Parasites Manipulate?mentioning

confidence: 99%

“…In elegant experiments using transformed viral strains, Hoover et al (2011) demonstrated that a single viral gene is responsible for the seemingly "Zombie"-like behavior of caterpillars that climb to the highest points of a tree instead of going down into the soil to pupate. The viral gene ecdysteroid-uridine diphosphateglucosyltransferase encodes an enzyme that inactivates the caterpillar's molting hormone by transferring a sugar moiety to it.…”

Section: Physiological Mechanismsmentioning

confidence: 99%

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Host Manipulation by Parasites: Cases, Patterns, and Remaining Doubts

Heil

2016

Front. Ecol. Evol.

105

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Parasites must overcome host immunity and change hosts for dispersal. Therefore, seemingly odd behaviors of parasitized animals, like those exhibited by "Zombie ants" or the "fatal attraction" of mammals to their predators, have been explained as the extended phenotype of parasites that manipulate their hosts for transmission enhancement. Manipulation has evolved in all major phylogenetic lineages of parasites but is not ubiquitous. In fact, the real frequency and relevance of manipulation is still matter of debate. Here, I highlight some of the most pertinent questions that arise if we aim at a broader understanding of the ecological relevance and evolutionary trajectory of manipulating parasites. Why are more parasites with a trophic mode of transmission manipulating their host than horizontally transmitted parasites? Why are the causal agents of sexually transmitted diseases (STDs) so rarely reported to manipulate their host? Why do parasites of animals usually manipulate their intermediate host, whereas many pathogens of plants manipulate their final host and then cause a "fatal attraction" of herbivores to the already infected plant? How can we distinguish manipulation effects from adaptive host responses to parasitization? Does manipulation cause a cost to certain parasites that can select against the evolution of manipulation? More emphasis should be put on direct comparisons among parasites of animals, plants, and humans. Manipulation for transmission enhancement should be studied in concert with manipulation for host immunity suppression, the molecular mechanisms that control the manipulation effect need to be deciphered, and we should test for alternative explanations for the observed phenotypic changes. Finally, we should quantify transmission rates and net fitness for manipulating and non-manipulating parasites, in ecologically realistic setups, to identify the forces that select against the evolution of manipulation. Ultimately, parasite net fitness represents the relevant outcome of any manipulation effect.Keywords: immunity, malaria, partner manipulation, pathogen, plant-enemy interaction, STDs, toxoplasmosis "FATAL ATTRACTION" AND MANIPULATING PARASITES Parasites represent a ubiquitous aspect in the life of multicellular organisms (Wood and Johnson, 2015) and most, if not all, of us have experienced how strongly an infection can interfere with our normal activities and well-being. Therefore, it might not appear to be too surprising when parasitized hosts exhibit behavioral alterations (see Glossary) as compared to healthy conspecifics.

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Section: Why Don't All Parasites Manipulate?mentioning

confidence: 99%

Section: Physiological Mechanismsmentioning

confidence: 99%

Host Manipulation by Parasites: Cases, Patterns, and Remaining Doubts

Heil

2016

Front. Ecol. Evol.

105

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“…Expression of viral proteases (cathepsin) and chitinase, late post infection, ensures that, in most alphabaculoviruses and in some betabaculoviruses, progeny OBs are released in the environment by lysing larval tissues and the exoskeleton of larvae following death (Hawtin et al, 1997;Hom et al, 2002). In addition, in silkmoth and gypsy moth, virally-produced proteins, tyrosine phosphatase (ptp) (Kamita et al, 2005) and ecdysteroid uridine 5´-diphosphate (UDP)-glucosyltransferase (egt) (Hoover et al, 2011), are responsible for behavioral changes that occur during the infection process where infected larvae leave their normal sheltered habitats and climb to exposed surfaces. This alteration in larval behaviour is thought to assist in virus distribution by facilitating predation by animals and by increasing exposure to elements.…”

Section: Disease Progression In Alphabaculovirusesmentioning

confidence: 99%

Recent Advances in Our Knowledge of Baculovirus Molecular Biology and Its Relevance for the Registration of Baculovirus-Based Products for Insect Pest Population Control

Lapointe¹,

Thumbi²,

Lucarotti³

2012

Integrated Pest Management and Pest Control - Current and Future Tactics

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“…This is especially evident in parasitism, where parasites modify the behaviors of their hosts in a way that is beneficial for the parasite. For example, insects infected by virus or fungus often tend to crawl up on the vegetation, which facilitates the spread of the infection (Hoover et al 2011). Mice infected by a single-cell parasite Toxoplasma gondii become attracted to cats' urine, which increases the chances of completing the life cycle of the parasite (Ingram et al 2013).…”

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confidence: 99%

Organisms Reshape Sign Relations

2015

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A key feature of biosemiotics is, in contrast with traditional semiotics, that it considers the dynamics of semiosis at multiple time scales, and emphasizes the active role organisms have in reshaping sign relations. Historically, semiotics has been focused either on the structural properties of signs systems or on the relations between sign vehicles, objects, and human interpretations. Questions about the origin and dynamics of sign relations have rarely been raised. Uexküll, who developed the foundational ideas of biosemiotics, was the first to propose that objects in the environment have specific meanings for different organisms. In his biological perspective, organisms have a pivotal role in developing their meaning relations with the environment. Uexküll (1926: 317) further observed that[t]he external world offers to the organism a certain number of properties separated in space and in time, from which to select, and therewith the possibility of making a poorer or a richer surrounding-world [Umwelt]. But the external world itself takes no part in the selection, which has to be made by the organism without external assistance.Uexküll's understanding of evolution departed from Darwin's ideas of environmentallydriven natural selection. He thought that organisms are active players in evolution, and that embryogenesis and animal behavior are mediated by the meanings that are associated with various objects (Magnus 2011; Brentari 2015: 60).The dynamic nature of sign relations and meanings has been emphasized e.g. in studies of child development in humans. Both Jean Piaget and Lev Vygotsky noted the role of sign-mediated processes in child development and described the developmental Biosemiotics (2015) 8:361-365

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A Gene for an Extended Phenotype

Cited by 203 publications

References 12 publications

Host Manipulation by Parasites: Cases, Patterns, and Remaining Doubts

Host Manipulation by Parasites: Cases, Patterns, and Remaining Doubts

Recent Advances in Our Knowledge of Baculovirus Molecular Biology and Its Relevance for the Registration of Baculovirus-Based Products for Insect Pest Population Control

Organisms Reshape Sign Relations

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