scholarly journals Evidence for clonal structure of natural populations of free-living amoebae of the genus Naegleria

1997 ◽  
Vol 69 (3) ◽  
pp. 173-181 ◽  
Author(s):  
PIERRE PERNIN ◽  
MARIE LOUISE CARIOU
Keyword(s):  
Related Species ◽  
Natural Populations ◽  
Enzyme Electrophoresis ◽  
Strong Linkage Disequilibrium ◽  
Closely Related Species ◽  
Multilocus Genotypes ◽  
In The Wild ◽  
Hardy Weinberg Equilibrium ◽  
Genetic Structures ◽  
Naegleria Gruberi

Genetic diversity of natural populations of the two species Naegleria gruberi and N. australiensis collected at the same time in the same area was studied using multilocus enzyme electrophoresis (MLEE analysis). Reference strains and related species were also analysed for comparison. Five loci were found to be polymorphic and allowed identification of 19 different multilocus genotypes among 67 isolates – eight for N. gruberi and 11 for N. australiensis – none being common to the two species. Large departures from Hardy–Weinberg equilibrium were found at all the loci, with significant heterozygote deficiencies in most cases. The two species exhibited strong linkage disequilibrium and the predominance of a few multilocus genotypes within each species was observed. These lines of evidence strongly suggest non-random association of alleles, leading to the conclusion that N. gruberi and N. australiensis have predominantly clonal genetic structures in the wild. Populations consist of a few major clones with some closely related ones – a structure found for several parasitic protozoans and bacteria. This contrasts with the panmictic structure found for N. lovaniensis, another species of this genus, and suggests that closely related species within the genus have evolved to have different reproductive strategies.

scholarly journals Living a dog’s life: a putative gray wolf in a feral dog group

Mammalia ◽  
2020 ◽  
Vol 84 (2) ◽  
pp. 115-120
Author(s):  
Elitsa Popova ◽  
Diana Zlatanova
Keyword(s):  
Related Species ◽  
Ecological Impact ◽  
Complex Interaction ◽  
Domestic Dog ◽  
Hybrid Origin ◽  
Mountainous Area ◽  
Gray Wolf ◽  
Closely Related Species ◽  
Feral Dogs ◽  
In The Wild

AbstractThe gray wolf and the domestic dog are closely related species that can interbreed and produce fertile offspring. In settings where unrestrained dogs are present in the wild, hybridization can happen naturally. However, the behavior of the resulting hybrids and their ecological impact is largely understudied. In September–November 2018, a putative gray wolf was repeatedly camera-trapped in a group of 10 presumably feral dogs in a remote mountainous area (the Osogovo Mountain) along the border between Bulgaria and North Macedonia. The most feasible explanation for this individual’s atypical behavior is that it is of hybrid origin (assumption based on phenotype). To the best of our knowledge, this is the first documented observation of such a kind. A discussion of its recruitment and position in the group is presented, setting the basis for further investigation of the complex interaction between wolves, dogs and hybrids in the wild.

Reproductive isolation between two closely related species of the Queensland fruit fly Dracus tryoni (Frogg) and D. neohumeralis Hardy (Diptera : Tephritidae) I. Variation in humeral callus pattern and the occurrence of intermediate colour forms in the wild

1967 ◽  
Vol 15 (3) ◽  
pp. 501 ◽  
Author(s):  
H Wolda
Keyword(s):  
Reproductive Isolation ◽  
Related Species ◽  
Fruit Fly ◽  
Abundant Species ◽  
Colour Pattern ◽  
Wild Populations ◽  
Closely Related Species ◽  
Similar Variation ◽  
In The Wild

A number of samples from wild populations of the Queensland fruit fly, Dacus tryoni and D. neohumeralis, were studied. There is a considerable variation in the colour pattern on the humeral callus. This variation is continuous so that any criterion for distinguishing between "intermediates" and "good species" is purely arbitrary. It was found in areas where D. neohumeralis does not occur as well as in localities where it is very abundant. By whatever criterion one defines intermediates, there appears to be no relation between the frequency of such forms and the presence or absence of D. neohumeralis or with the relative proportions of the two species in the population. However, flies with only a very small yellow area on an otherwise brown humeral callus were found only in Cairns where D. neohumeralis is usually the most abundant species. A similar variation in humeral callus pattern was found in other related species, such as D. kraussi and D. halfordiae. It is concluded that the intermediate colour forms may not be hybrids between D. tryoni and D. neohumeralis but variants of D. tryoni and, possibly the darker forms from Cairns, of D. neohumeralis.

scholarly journals Lack of underdominance in a naturally occurring pericentric inversion in Drosophila melanogaster and its implications for chromosome evolution.

Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 791-802
Author(s):  
J A Coyne ◽  
S Aulard ◽  
A Berry
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Genetic Drift ◽  
Related Species ◽  
Pericentric Inversion ◽  
Chromosome Evolution ◽  
Natural Populations ◽  
Crossing Over ◽  
Closely Related Species ◽  
Naturally Occurring

Abstract In(2LR)PL is a large pericentric inversion polymorphic in populations of Drosophila melanogaster on two Indian Ocean islands. This polymorphism is puzzling: because crossing over in female heterokaryotypes produces inviable zygotes, such inversions are thought to be underdominant and should be quickly eliminated from populations. The observed fixation for such inversions among related species has led to the idea that genetic drift can cause chromosome evolution in opposition to natural selection. We found, however, that In(2LR)PL is not underdominant for fertility, as heterokaryotypic females produce perfectly viable eggs. Genetic analysis shows that the lack of underdominance results from the nearly complete absence of crossing over in the inverted region. This phenomenon is probably caused by mechanical and not genetic factors, because crossing over is not suppressed in In(2LR)PL homokaryotypes. Our observations do not support the idea that the fixation of pericentric inversions among closely related species implies the action of genetic drift overcoming strong natural selection in very small populations. If chromosome arrangements vary in their underdominance, it is those with the least disadvantage as heterozygotes, like In(2LR)PL, that will be polymorphic or fixed in natural populations.

The Pollination Biology of Dendrobium speciosum Smith: a Case of False Advertising?

1988 ◽  
Vol 36 (2) ◽  
pp. 145 ◽  
Author(s):  
AT Slater ◽  
DM Calder
Keyword(s):  
Related Species ◽  
Fruit Set ◽  
Natural Populations ◽  
Climatic Conditions ◽  
Closely Related Species ◽  
High Occurrence ◽  
Bright Yellow ◽  
Pollination Mechanisms ◽  
Sunny Weather ◽  
Olfactory Display

Potential pollinators of Dendrobium speciosum are attracted to the plant by large, cream to yellow, finely segmented, aromatic inflorescences. Plants in natural populations flower synchronously, produc- ing a massive display. Osmophores scattered over the perianth produce a strong, sweet scent in sunny weather. Nectar-seeking insects are guided to the central, reproductive area of the flower by the colour gradation of the perianth, including an area of high U.V. reflection near the centre, and a bright yellow ridge along the labellum. A tube formed by the labellum and column directs the potential pollinators. The flower, however, produces no nectar. Flowers vary in size within the six recognised varieties of D. speciosum and are pollinated when visited by bees of appropriate size. Post-pollination closure of flowers prevents further access by potential pollinators. The dendrobium beetle and larvae feed on the plant and inflorescences and play no part in pollination. The low fruit set, characteristic of this species, is considered to be a combined result of self-infertility and the absence of rewards offered by the flower. The specific climatic conditions during which pollinators visit the flowers are also important. The attraction and pollination mechanisms are similar among all observed varieties of D. speciosum as well as some closely related species, possibly explaining the high occurrence of hybrids within this group. It is concluded that D. speciosum provides a visual and olfactory display through the production of a large number of hermaphrodite non-rewarding flowers on each inflorescence, and relies on infrequent outcrosses for successful pollination.

scholarly journals Species integrity enhanced by a predation cost to hybrids in the wild

2017 ◽  
Vol 13 (7) ◽  
pp. 20170208 ◽  
Author(s):  
P. Anders Nilsson ◽  
Kaj Hulthén ◽  
Ben B. Chapman ◽  
Lars-Anders Hansson ◽  
Jakob Brodersen ◽  
...  
Keyword(s):  
Related Species ◽  
Parental Species ◽  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Hybrid Fitness ◽  
Closely Related Species ◽  
Ecological Selection ◽  
Field Evidence ◽  
In The Wild ◽  
Species Integrity

Species integrity can be challenged, and even eroded, if closely related species can hybridize and produce fertile offspring of comparable fitness to that of parental species. The maintenance of newly diverged or closely related species therefore hinges on the establishment and effectiveness of pre- and/or post-zygotic reproductive barriers. Ecological selection, including predation, is often presumed to contribute to reduced hybrid fitness, but field evidence for a predation cost to hybridization remains elusive. Here we provide proof-of-concept for predation on hybrids being a postzygotic barrier to gene flow in the wild. Cyprinid fishes commonly produce fertile, viable hybrid offspring and therefore make excellent study organisms to investigate ecological costs to hybrids. We electronically tagged two freshwater cyprinid fish species (roach Rutilus rutilus and bream Abramis brama ) and their hybrids in 2005. Tagged fish were returned to their lake of origin, exposing them to natural predation risk from apex avian predators (great cormorant, Phalacrocorax carbo ). Scanning for regurgitated tags under cormorant roosts 3–4 years later identified cormorant-killed individual fish and allowed us to directly test for a predation cost to hybrids in the wild. Hybrid individuals were found significantly more susceptible to cormorant predation than individuals from either parental species. Such ecological selection against hybrids contributes to species integrity, and can enhance species diversification.

Population structure and genetic typing of Trypanosoma cruzi, the agent of Chagas disease: a multilocus enzyme electrophoresis approach

Parasitology ◽  
2000 ◽  
Vol 120 (5) ◽  
pp. 513-526 ◽  
Author(s):  
C. BARNABÉ ◽  
S. BRISSE ◽  
M. TIBAYRENC
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Natural Populations ◽  
Enzyme Electrophoresis ◽  
Strong Linkage Disequilibrium ◽  
Multilocus Enzyme Electrophoresis ◽  
Routine Identification ◽  
Genetic Clusters ◽  
Phylogenetic Lineages ◽  
The Impact

A set of 434 Trypanosoma cruzi stocks from a wide ecogeographical range was analysed by Multilocus Enzyme Electrophoresis for 22 genetic loci. Strong linkage disequilibrium, not associated with geographical distance, and 2 main genetic clusters each considerably heterogeneous, was observed. These results support the hypotheses previously proposed that T. cruzi natural populations are composed of highly diversified genetic clones distributed into 2 main phylogenetic lineages: lineage 1, the most ubiquitous in the endemic area, was more frequently observed in sylvatic cycles, whereas lineage 2, predominant in humans and domestic cycles, in the southern part of the area surveyed, was further partitioned into 5 lesser genetic subdivisions. T. cruzi appears therefore subdivided into at least 6 ‘discrete typing units’ or DTUs (Tibayrenc, 1998a–c). We have identified various specific isoenzyme markers (‘tags’; Tibayrenc, op. cit.) suitable for the routine identification of these DTUs for epidemiological tracking purposes. We discuss the correspondence with previous classifications and with the recent recommendations of the 90th anniversary of the discovery of Chagas disease symposium, as well as the impact of T. cruzi genetic variability on this parasite's biomedical diversity.

Revision of the European Aethes rubigana complex with a description of genetically confirmed Aethes kyrkii sp. n. (Lepidoptera, Tortricidae)

2003 ◽  
Vol 34 (1) ◽  
pp. 3-14 ◽  
Author(s):  
Pekka Lankinen ◽  
Juhani Itämies ◽  
Marko Mutanen
Keyword(s):  
New Species ◽  
Related Species ◽  
Taxonomic Status ◽  
Statistical Analyses ◽  
Enzyme Electrophoresis ◽  
Genetic Isolation ◽  
Closely Related Species ◽  
Palearctic Region ◽  
A New Species

AbstractThe Aethes rubigana complex is shown to comprise four closely related species in the Palearctic region: Eurasian Aethes cnicana (Westwood, 1854), European A. rubigana (Treitschke, 1830), Asiatic A. citreoflava V. I. Kuznetsov, 1966, and A. kyrkii, here described as a new species from northern Finland. A. kyrkii is morphologically most close to A. cnicana, but enzyme electrophoresis revealed complete genetic isolation between them. Descriptions are given of the three species occurring in Europe, and their respective biologies are outlined. Statistical analyses of traits of the forewing are given. The taxonomic status of A. arcticana (Brandt, 1937) is revised.

scholarly journals A pre-zygotic barrier to hybridization in two con-generic species of scleractinian corals

F1000Research ◽  
2013 ◽  
Vol 2 ◽  
pp. 193 ◽  
Author(s):  
Andrew H. Baird ◽  
Vivian R. Cumbo ◽  
Joana Figueiredo ◽  
Saki Harii
Keyword(s):  
Related Species ◽  
Scleractinian Corals ◽  
Evolutionary Novelty ◽  
Closely Related Species ◽  
Potential Source ◽  
The Family ◽  
Growing Body ◽  
In The Wild

Hybridization is often cited as a potential source of evolutionary novelty in the order Scleractinia. While hybrid embryos can be produced in vitro, it has been difficult to identify adult hybrids in the wild. Here, we tested the potential for hybridization between two closely related species in the family Fungiidae. We mixed approximately 5000 eggs of Ctenactis echinata with sperm from Ctenactis crass. No hybrid embryos were produced. This observation adds to a growing body of evidence for pre-zygotic barriers to hybridization in corals and challenges the claim that hybridization is a major source of evolutionary novelty in the order.

scholarly journals Rearing animals in captivity for the study of trematode life histories. II

1940 ◽  
Vol 24 (2) ◽  
pp. 613-617 ◽  
Author(s):  
Miriam Rothschild
Keyword(s):  
Related Species ◽  
Life Histories ◽  
Adult Fluke ◽  
Morphological Comparison ◽  
Closely Related Species ◽  
In Captivity ◽  
Previous Infection ◽  
In The Wild

The advantage of using laboratory-reared animals in the elucidation of trematode life histories is now generally recognized (Palombi, 1938; Stunkard, 1938, etc.). Further researches seem to emphasize this point. No matter how carefully controls are examined and no matter how precise is the morphological comparison between cercaria, metacercaria and adult fluke, the fact that the intermediate and final hosts have been exposed to previous infection in the wild—particularly by closely related species of worms—immediately detracts from the value of the experiments.

scholarly journals A fruit in the hand or two in the bush? Divergent risk preferences in chimpanzees and bonobos

2008 ◽  
Vol 4 (3) ◽  
pp. 246-249 ◽  
Author(s):  
Sarah R Heilbronner ◽  
Alexandra G Rosati ◽  
Jeffrey R Stevens ◽  
Brian Hare ◽  
Marc D Hauser
Keyword(s):  
Decision Making ◽  
Related Species ◽  
Pan Paniscus ◽  
Risk Preferences ◽  
Food Sources ◽  
Closely Related Species ◽  
Economic Choice ◽  
Economic Decision Making ◽  
Risk Sensitive ◽  
In The Wild

Human and non-human animals tend to avoid risky prospects. If such patterns of economic choice are adaptive, risk preferences should reflect the typical decision-making environments faced by organisms. However, this approach has not been widely used to examine the risk sensitivity in closely related species with different ecologies. Here, we experimentally examined risk-sensitive behaviour in chimpanzees ( Pan troglodytes ) and bonobos ( Pan paniscus ), closely related species whose distinct ecologies are thought to be the major selective force shaping their unique behavioural repertoires. Because chimpanzees exploit riskier food sources in the wild, we predicted that they would exhibit greater tolerance for risk in choices about food. Results confirmed this prediction: chimpanzees significantly preferred the risky option, whereas bonobos preferred the fixed option. These results provide a relatively rare example of risk-prone behaviour in the context of gains and show how ecological pressures can sculpt economic decision making.

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