Search results for "Polymorphism"

The genome sequencing of an albino Western lowland gorilla reveals inbreeding in the wild

2013

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License.-- et al.

Nested core collections maximizing genetic diversity in Arabidopsis thaliana.

2004

Summary The successful exploitation of natural genetic diversity requires a basic knowledge of the extent of the variation present in a species. To study natural variation in Arabidopsis thaliana, we defined nested core collections maximizing the diversity present among a worldwide set of 265 accessions. The core collections were generated based on DNA sequence data from a limited number of fragments evenly distributed in the genome and were shown to successfully capture the molecular diversity in other loci as well as the morphological diversity. The core collections are available to the scientific community and thus provide an important resource for the study of genetic variation and its …

Degradation of sexual reproduction in Veronica filiformis after introduction to Europe

2011

Abstract Background Baker’s law predicts that self-incompatible plant species are generally poor colonizers because their mating system requires a high diversity of genetically differentiated individuals and thus self-compatibility should develop after long-distance dispersal. However, cases like the introduction of the self-incompatible Veronica filiformis (Plantaginaceae) to Europe constitute an often overlooked alternative to this rule. This species was introduced from subalpine areas of the Pontic-Caucasian Mountains and colonized many parts of Central and Western Europe in the last century, apparently without producing seeds. To investigate the consequences of the absence of sexual rep…

Gray plumage color is more cryptic than brown in snowy landscapes in a resident color polymorphic bird

2020

Abstract Camouflage may promote fitness of given phenotypes in different environments. The tawny owl (Strix aluco) is a color polymorphic species with a gray and brown morph resident in the Western Palearctic. A strong selection pressure against the brown morph during snowy and cold winters has been documented earlier, but the selection mechanisms remain unresolved. Here, we hypothesize that selection favors the gray morph because it is better camouflaged against predators and mobbers in snowy conditions compared to the brown one. We conducted an online citizen science experiment where volunteers were asked to locate a gray or a brown tawny owl specimen from pictures taken in snowy and snow…

Isolation and characterization of nonpathogenic Fusarium oxysporum isolates from the rhizosphere of healthy banana plants

2006

Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699; One of the most serious diseases of banana is fusarium wilt, caused by Fusarium oxysporum f.sp. cubense (Foc). The objectives of this study were to isolate and identify nonpathogenic F. oxysporum strains from soils suppressive to banana wilt, and to determine the diversity of these isolates. More than 100 Fusarium strains were isolated from the rhizosphere of banana plants and identified to species level. Pathogenicity testing was carried out to confirm that these isolates were nonp…

Overcompensation as a mechanism for maintaining polymorphism: egg-to-adult viability in Drosophila.

1990

Frequency-dependent selection may be accounted for, in ecological terms, by the differential effectiveness of alternative genotypes in exploiting limiting environmental resources. Differentiation in resource exploitation among genotypes implies in turn that a mix of genotypes may exploit more fully the resources than a genetically uniform population, a phenomenon called 'overcompensation' Experiments designed to test for overcompensation whow that highly polymorphic populations can support larger numbers of individuals per food unit than less polymorphic populations. This difference cannot be attributed to the level of individual heterozygosity, which is the same in both types of population…

Gentics of hilanenus colour polymorphism: the 28 genotypes.

2009

Multilocus typing for characterization of ‘Candidatus Phytoplasma asteris’-related strains in several ornamental species in Italy

2018

Different ornamental plants showing symptoms referable to phytoplasma presence and collected between 1993 and 2015 in various floricultural areas in north and south of Italy, enclosing Sicily, resulted to be infected by ‘Candidatus Phytoplasma asteris’-related strains, and after PCR/RFLP identification on 16Sr gene were assigned to 16SrI-B subgroup. These infected samples were employed for phytoplasma strain differentiation on tuf, groel, rp and amp genes. In particular, the 23 phytoplasma strains employed were from hydrangea (5), primula (3), gentian (2), petunia (2) and gerbera (1) samples showing flower virescence; from gladiolus samples both in vivo and in micropropagation (2) showing t…

Disentangling phylogeography, polyploid evolution and taxonomy of a woodland herb (Veronica chamaedrys group, Plantaginaceae s.l.) in southeastern Eu…

2010

Southeastern Europe is a centre of European biodiversity, but very little is known about factors causing the observed richness. Here, we contribute to fill this gap by reconstructing the spatio-temporal diversification of the cytologically variable and taxonomically intricate complex of Veronica chamaedrys (Plantaginaceae s.l.), growing in open forests, forest edges and grasslands, with flow cytometry, molecular markers (AFLPs, plastid DNA sequences) and morphometry. Our results show that both diploid and tetraploid cytotypes are widespread, but diploids predominate on the southern Balkan Peninsula. Plastid sequences suggest a first split into three main lineages in the mid-Pleistocene and …

Genomic variation in tomato, from wild ancestors to contemporary breeding accessions

2015

[EN] Background: Domestication modifies the genomic variation of species. Quantifying this variation provides insights into the domestication process, facilitates the management of resources used by breeders and germplasm centers, and enables the design of experiments to associate traits with genes. We described and analyzed the genetic diversity of 1,008 tomato accessions including Solanum lycopersicum var. lycopersicum (SLL), S. lycopersicum var. cerasiforme (SLC), and S. pimpinellifolium (SP) that were genotyped using 7,720 SNPs. Additionally, we explored the allelic frequency of six loci affecting fruit weight and shape to infer patterns of selection. Results: Our results revealed a pat…