Search results for "VARIATION"

Genetic variability in environmental isolates of Legionella pneumophila from Comunidad Valenciana (Spain).

2006

Summary Legionella pneumophila is associated to recurrent outbreaks in several Comunidad Valenciana (Spain) localities, especially in Alcoi, where social and climatic conditions seem to provide an excellent environment for bacterial growth. We have analysed the nucleotide sequences of three loci from 25 environmental isolates from Alcoi and nearby locations sampled over 3 years. The analysis of these isolates has revealed a substan- tial level of genetic variation, with consistent patterns of variability across loci, and comparable to that found in a large, European-wide sampling of clinical isolates. Among the tree loci studied, fliC showed the highest level of nucleotide diversity. The an…

Characterization of mutations and sequence variations in complex STR loci by second generation sequencing

2013

Abstract We used second generation sequencing (SGS) to examine sequence variation and mutational patterns in complex STR loci in Danish paternity cases. Four STR loci, D2S1338, D3S1358, D12S391 and D21S11, were sequenced in 45 samples from 15 confirmed trios with genetic inconsistencies between one of the parents and the child in either the D2S1338 or the D3S1358 loci. In 12 of the 15 cases, SGS revealed the allele that had mutated from the parent. In total, 61 different alleles were found in the 30 unrelated individuals. The highest variation was observed in the D12S391 locus and the lowest one in the D3S1358 locus. The four STR loci are good candidate loci for future SGS kits for forensic…

Genetic analysis of Citrus aurantium L. (Rutaceae) cultivars by ISSR molecular markers

2011

Eight cultivars of Citrus aurantium L., showing peculiar morphological traits of the fruits and leaves, were analyzed genetically. Inter simple sequence repeat (ISSR) was chosen as molecular markers because they represent a highly efficient system for investigating variability at intraspecific level. The particular morphological traits were discussed, the genetic identity and distance matrix based on Nei index was calculated, and the unweighted pair group method with arithmetic mean (UPGMA) dendrogram was generated. A total of 53 clearly distinguished DNA bands were considered for the ISSR analysis of which 24 were polymorphic. A basic C. aurantium fingerprinting pattern was obtained. The I…

Genic capture and resolving the lek paradox

2006

The genic capture hypothesis offers a resolution to the question of how genetic variation in male sexually selected traits is maintained in the face of strong female preferences. The hypothesis is that male display traits are costly to produce and hence depend upon overall condition, which itself is dependent upon genes at many loci. Few attempts have been made to test the assumptions and predictions of the genic capture hypothesis rigorously and, in particular, little attention has been paid to determining the genetic basis of condition. Such tests are crucial to our understanding of the maintenance of genetic variation and in the evaluation of recent models that propose a role for sexual …

Systematic screening for mutations in the promoter and the coding region of the 5-HT1A gene.

1995

In the present study we sought to identify genetic variation in the 5-HT{sub 1A} receptor gene which through alteration of protein function or level of expression might contribute to the genetic predisposition to neuropsychiatric diseases. Genomic DNA samples from 159 unrelated subjects (including 45 schizophrenic, 46 bipolar affective, and 43 patients with Tourette`s syndrome, as well as 25 healthy controls) were investigated by single-strand conformation analysis. Overlapping PCR (polymerase chain reaction) fragments covered the whole coding sequence as well as the 5{prime} untranslated region of the 5-HT{sub 1A} gene. The region upstream to the coding sequence we investigated contains a …

COMPARING EVOLVABILITIES: COMMON ERRORS SURROUNDING THE CALCULATION AND USE OF COEFFICIENTS OF ADDITIVE GENETIC VARIATION

2012

In 1992, David Houle showed that measures of additive genetic variation standardized by the trait mean, CVA (the coefficient of additive genetic variation) and its square (IA), are suitable measures of evolvability. CVA has been used widely to compare patterns of genetic variation. However, the use of CVAs for comparative purposes relies critically on the correct calculation of this parameter. We reviewed a sample of quantitative genetic studies, focusing on sire models, and found that 45% of studies use incorrect methods for calculating CVA and that practices that render these coefficients meaningless are frequent. This may have important consequences for conclusions drawn from comparative…

Evaluation of different genetic procedures for the generation of artificial hybrids in Saccharomyces genus for winemaking

2012

Several methods based on recombinant DNA techniques have been proposed for yeast strain improvement; however, the most relevant oenological traits depend on a multitude of loci, making these techniques difficult to apply. In this way, hybridization techniques involving two complete genomes became interesting. Natural hybrid strains between different Saccharomyces species have been detected in diverse fermented beverages including wine, cider and beer. These hybrids seem to be better adapted to fluctuating situations typically observed in fermentations due to the acquisition of particular physiological properties of both parental strains. In this work we evaluated the usefulness of three dif…

Invasion biology and host specificity of the grapevine yellows disease vector Hyalesthes obsoletus in Europe

2008

Within the past 10 years, the yellows disease ‘bois noir’ (BN) has become one of the commercially most important diseases of grapevine [ Vitis vinifera L. (Vitaceae)] in Europe. Infection pressure is caused by phytoplasmas of the stolbur 16SrXII-A group that are transmitted by a planthopper vector, Hyalesthes obsoletus Signoret (Homoptera: Auchenorrhyncha). Infestation happens as an accidental side-effect of the feeding behaviour of the vector, as vector and pathogen proliferation is dependent on other plants. In Germany, the increase of BN is correlated with the use of a new host plant by the vector, increase in abundance of the vector on the new host plant, and dissemination of host plant…

2004

Background Genetic variability in viral populations is usually estimated by means of polymerase chain reaction (PCR) based methods in which the relative abundance of each amplicon is assumed to be proportional to the frequency of the corresponding template in the initial sample. Although bias in template-to-product ratios has been described before, its relevance in describing viral genetic variability at the intrapatient level has not been fully assessed yet.

Phylogenetic relationships between Drosophila subobscura, D. guanche and D. madeirensis based on Southern analysis of heat shock genes.

2004

A Southern analysis of genomic DNA using Drosophila melanogaster probes for the major heat shock protein genes (Hsp82, Hsp 70, Hsps encoding small proteins) was made to study the phylogenetic relationships between three Drosophila species belonging to the obscura group (D. subobscura, D. guanche, and D. madeirensis). The phylogenetic trees showed that D. madeirensis and D. subobscura are the most closely related species in the triad, while D. guanche is the most distantly related one. As in other Drosophila species, Hsp82 is a single copy gene in D. subobscura, D. guanche, and D. madeirensis, while Hsp 70 and Hsps, which encode small proteins, are genie families. At least four sequences hom…