The deme terminology and the units of micro-evolutionary change

Gilmour, J. S. L.; Heslop‐Harrison, J.

doi:10.1007/bf01664158

Cited by 79 publications

(25 citation statements)

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“…We propose to designate those populations displaying identical or similar kDNA minicircle restriction patterns by the term "schizodeme" (schizo, to split) (27,28).…”

Section: Resultsmentioning

confidence: 99%

Strains and clones of Trypanosoma cruzi can be characterized by pattern of restriction endonuclease products of kinetoplast DNA minicircles.

Morel¹,

Chiari²,

Camargo³

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

254

105

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A simple method was developed for the characterization of different strains of Tiypanosoma cruzi. T. cruzi stocks isolated from vectors or by hemoculture from patients with Chagas disease could be grouped in subpopulations having similar patterns of restriction endonuclease products of kinetoplast DNA minicircles. We designate such subpopulations by the term "schizodemes." Furthermore, it is shown that, from a given T. cruzi strain, clones with different biological properties can be isolated and identified by their restriction patterns.The hemoflagellate Trypanosoma cruzi is the etiological agent of Chagas disease, a pleomorphic clinical entity that is an important cause of morbidity and mortality in Central and South America. In some patients the infection is devastating from the very beginning with death occurring after a short acute phase; meningoencephalitis and myocarditis are prominent findings. In other cases, however, the acute phase is oligosymptomatic or even silent and may evolve without detectable sequels. Between these two extremes, in most cases the course has a variable acute phase which subsides in a few weeks, to be followed years later by digestive or cardiac symptoms or both (1).The exact causes of this clinical pleomorphism are not known, although evidence suggests that both host and parasite factors may be involved (1). In terms of the parasite, differences have been found among several strains of T. cruzi in regard to morphology, virulence, pathogenicity, and tissue tropism (1). Particularly well documented are the differences between the "polar" Y (2) and CL (3) strains. Isozyme analysis has also been used to distinguish strains of T. cruzi. Miles et al. (4-6) examined T. cruzi stocks isolated from humans and sylvatic animals in Brazil and found three distinct isozyme groups (or zymodemes). Romanha et al. (7,8) studied T. cruzi cultures obtained from humans in the city of Bambui (Minas Gerais, Brazil) and were able to group the stocks into four isozyme groups. Variations in kinetoplast DNA (kDNA) buoyant density between strains of T. cruzi and strains and species of Leishmania have been reported, and this classification method has been used by Chance (9) and Baker et al. (10).Comparison of restriction endonuclease-generated fragments of kDNA has been proposed as another method for the intrinsic classification of trypanosomes (11,12). We show here that stocks of T. cruzi isolated from patients with Chagas disease can be characterized by restriction digests of the kDNA networks. MATERIALS AND METHODSCells. With the exception of the strains Y and CL (13), all the T. cruzi stocks used in this study were obtained from patients who had positive serologic tests against Chagas disease and who were from the city of Bambui (Minas Gerais, Brazil). Stock cultures were initiated with cells-from 30 ml of blood, grown to stationary phase in liver infusion/tryptose medium (14) at 270C, and stored frozen in liquid nitrogen. Clinical histories are available for each human isolate used in this study...

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“…We propose to designate those populations displaying identical or similar kDNA minicircle restriction patterns by the term "schizodeme" (schizo, to split) (27,28).…”

Section: Resultsmentioning

confidence: 99%

Strains and clones of Trypanosoma cruzi can be characterized by pattern of restriction endonuclease products of kinetoplast DNA minicircles.

Morel¹,

Chiari²,

Camargo³

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

254

105

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“…But such lack of uniformity cannot be to the advantage of biology as a whole. The most comprehensive reform of species nomenclature is the deme terminology (Gilmour and Gregor, 1939;Gilmour and Heslop-Harrison, 1954), badly misunderstood by many workers, who have used "deme" only for a geographically definable population of sexually reproducing organisms.…”

Section: Definitions Of Taxonomic Categoriesmentioning

confidence: 99%

Recent Developments in Theoretical and Quantitative Taxonomy

Sneath¹

1961

Systematic Zoology

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“…In this significance, deme denotes "any group of individuals of a specified taxon" -the word "group" in this phrase to "indicate even more unequivocally that no idea of 'population' entres into the definition of the root'deme')." (GILMOUR and HESLOP-HARRISON 1954) This deme-terminology seems, however, hardly to have filled any requirement at all. MAYR (1963) thus emphasises, that "the term 'deme' in its original publication is nothing but a needless synonym for the prior term ' population"' and finds it appropriate to give to the word a more specific meaning, intending to use "deme" to denote "the local population, the interbreeding community" as was already done by several zoologists, e.g .…”

Section: Demementioning

confidence: 99%

Revising some terms of intra-specific differentiation

Langlet¹

2009

Hereditas

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Some terms, universally used in botany and zoology, are rather vaguely defined, if at all, and have in common use become to such an extent ambiguous, that they need recurrent re-definitions to avoid confusion. For that it is necessary to give to them definite significations, as far as possible in accordance with their current use. The terms here considered are: variationvariability-variousness; cline; deme; and ecotype. Variation-variability-variousnessAbout the beginning of this century, de VRIES (1901) considered nothing to be more variable than the meaning of the word variability and the same opinion had been even more relevant in respect of the word variation.DARWIN seems consistently to have used variation and variability undiscriminately and like many later authors apparently interchanged the terms merely in order to avoid monotony.However, about the turn of the century there were made some efforts t o define these terms. JORDAN (1905) did clearly discriminate the variability as a state of being diverse from the geographical variation as a process of getting diverse within a species. Later, JENNINGS (1909) emphasised the ". . . great importance to distinguish variation as a process from variation as an existing static condition of diversity", although without any discriminating terminology. PETER (191 I), who apparently did not know of JORDAN'S paper more than of JENNINGS', defines "Variation" as a process of getting diverse and "Variabilitat" as a static condition of dissimilarity. The same definitions were rendered by PHILIPT-SCHENKO (1 926), who also reviewed the earlier literature, with exception of the pioneer JORDAN.In spite of his definitions, it seems that PETER mainly bothered about the difference between variation as a process and as a capability of diversification. Obviously the simple word variation is that ambiguous, that it represents at least three definitely different ideas. In order to discern distinctly between all the three meanings which the word variation up till now is used t o express, I propose to use the following words specifically and thus as scientific terms:Variation exclusively as a verb to denote the Variability to denote an abstract ability to vary;Variousness to denote a concrete existing condiprocess of varying; tion of being various.Variousness, as the result of a variation, whichlin turn is rendered possible through an existing variability, is thus synonymous with dissimilarity, diversity, unlikeness and difference (as a condition). It seems to me, however, that the word variousness is preferable as a term, first on account of its being directly derived from various and thus linguistically related t o variation, secondly because of its being used rather rarely in ordinary language.For my own part I have since 1936 (LANGLET 1936) adopted the term variability in the sense of JORDAN and PHILIPTSCHENKO and as it has later been redefined by THODAY (1953) and as it is now widely used in the biological literature.

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The deme terminology and the units of micro-evolutionary change

Cited by 79 publications

References 8 publications

Strains and clones of Trypanosoma cruzi can be characterized by pattern of restriction endonuclease products of kinetoplast DNA minicircles.

Strains and clones of Trypanosoma cruzi can be characterized by pattern of restriction endonuclease products of kinetoplast DNA minicircles.

Recent Developments in Theoretical and Quantitative Taxonomy

Revising some terms of intra-specific differentiation

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