The Interaction of Nucleus and Cytoplasm in the Isolation and Evolution of Species of Paramecium

Levine, Myron M.

doi:10.2307/2405345

Cited by 10 publications

(3 citation statements)

References 2 publications

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“…Sorting all the available stocks that corresponded to the general description of the nominal species P. aurelia into those that could or could not breed, Sonneborn (l939b) came out with different mating groups, each comprising a set of two mating types (referred to as "Odd" and "Even"). The reproductive isolation of mating groups was complete, supported by either premating and/or postmating isolation mechanisms (Sonneborn, 1974); no introgression could be demonstrated (Levine, 1953;Haggard, 1974). Sonneborn (1947) suddenly recognized that these mating groups were good "biological species" with no gene flow between them (referred to as "full genetic species"), but refrained from according them specific binomial designations because their identification by means of tests with standard living reference stocks was burdensome, more than could reasonably be expected for routine identification.…”

Section: The Genetic Species Paradigmmentioning

confidence: 94%

Sex in Ciliates

Dini

Nyberg

1993

Advances in Microbial Ecology

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Section: The Genetic Species Paradigmmentioning

confidence: 94%

Sex in Ciliates

Dini

Nyberg

1993

Advances in Microbial Ecology

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“…An important class of chemical biotic factors which make for isolation is based on serological incompatibility. Even in Paramecium aurelia the intersterility between the eight varieties or 'species' seems due to incompatibility of the cytoplasm of one with the nucleus of the other (Levine, 1953). Precipitin and agglutinin tests are widely used for indicating the existence of specific proteins in blood, seminal fluid and other body fluids of animals and for indicating some degree of protein relationship by the intensity of the precipitin test.…”

Section: (A) Behawiourmentioning

confidence: 99%

Physiological Variation in Animals

Prosser

1955

Biological Reviews

208

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SUMMARY Numerous examples are cited of physiological characters which, like morphological characters, vary genotypically, ontogenetically or phenotypically. Physiological variation is useful in describing interspecific relations, intraspecific variation and the limits of ecological range. Physiological variation of a character permits the establishment of populations at environmental limits and thus predisposes a race for genetic fixation of a character (Baldwin effect). Such variation is primary in providing one mechanism of reproductive isolation. Secondary physiological variation functions in habitat selection, particularly after reproductive isolation. Criteria for physiological variation are given by measurement of internal state in relation to environmental stress. In regulators a criterion is the point of failure of homeostatic mechanisms; in adjusters a criterion is the limit of tolerance after maximum acclimation. Both regulation and adjustment are adaptive to environmental change; in both types, phenotypic variation must be distinguished from genotypic variation. Examples of physiological variation in osmotic adaptation, in different populations of the same species, are given for species of Paramecium, Euplotes, Asterias, Gammarus, Callinectes, Anopheles, Onchorhynchus and Gasterosteus. Genetically different races have been established for Gasterosteus aculeatus and Euplotes vassus. Ionic balance has been little studied as a basis for variation of populations but specific requirements for some elements, such as copper and calcium, may have led to local differences. Stress of temperature extremes has induced many physiological variants. Closely related large homoiotherms differ in insulating capacity, smaller species differ also in metabolic response, particularly to cold. Poikilotherms differ in tolerance limits after acclimation, in ‘selected’ temperatures, in metabolic level according to their temperature history, in Q10, in critical temperatures for reproduction and development. Physiological races with respect to temperature tolerance or selection are cited for species of Notropis, Micropterus, Gambusia, Pandalus and Carabus. Examples of metabolic differences in populations are found in aquatic but not terrestrial poikilotherms. Examples of races with respect to optimal temperature of development are found in species of Paramecium, Crassostrea, Urosalpinx, Daphnia, Drosophila, Lymantria and Rana. Criteria of variation with respect to oxygen are the half‐saturation value of transport pigments, the critical oxygen concentration, metabolic level, tolerance of products of anaerobiosis, auxiliary breathing mechanisms and stimulation of pigment development by hypoxia. Correlations of these functions with history of oxygen availability are cited, but data are inadequate to establish genetic races. Selection of specific food plants depends on secondary products, not primary food; many subspecies and races are known by food plant selection, especially among bugs, gall flies and butterflies. Preference can ...

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“…First. attempts to relate the diverse breeding systems uncovered among various species of ciliates to a recognizable pattern of evolution ( 11,21,22,16,15) obviously depend upon the assumption that conjugation is not simply a laboratory phenomenon. Second, those experiments which prove heterosis( 1 7 ) and a high frequency of conjugation in artificial populations ( 1 0 ) take on additional significance if genetic exchanges do indeed occur in nature.…”

Section: R W Siegelmentioning

confidence: 99%

Direct and Indirect Evidence that Free‐living Ciliates Conjugate in Nature*

Siegel

1961

The Journal of Protozoology

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A brief summary of the literature exemplifying the indirect lines of evidence leading to the conclusion that ‐living ciliates conjugate in natural environments is followed by a description of the isolation of potential mates, conjugating pairs and recent exconjugants of Paramecium bur‐saria from a pond in Westwood Village. Calif. The data suggest that natural populations of Paramecium pursaria pass through infrequent epidemics of conjugation.

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The Interaction of Nucleus and Cytoplasm in the Isolation and Evolution of Species of Paramecium

Cited by 10 publications

References 2 publications

Sex in Ciliates

Sex in Ciliates

Physiological Variation in Animals

Direct and Indirect Evidence that Free‐living Ciliates Conjugate in Nature*

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