Search results for " variability"

Characterization of 10 trinucleotide microsatellite loci in the Critically Endangered Pyrenean yam Borderea chouardii (Dioscoreaceae)

2003

The low levels of allozymic variability found in the Critically Endangered Borderea chouardii prompted us to develop microsatellite markers to assess the genetic variability and population structure for the adequate conservation management of this species. A (CTT) n enriched partial genomic library was constructed. Ten polymorphic microsatellite loci were isolated from it, rendering 51 alleles in 47 individuals analysed. The allelic pattern observed for all of the loci with more than two alleles suggests that B. chouardii is tetraploid.

The genome-wide structure of two economically important indigenous Sicilian cattle breeds1

2014

Genomic technologies, such as high- throughput genotyping based on SNP arrays, provided background information concerning genome structure in domestic animals. The aim of this work was to inves- tigate the genetic structure, the genome-wide estimates of inbreeding, coancestry, effective population size (N e ), and the patterns of linkage disequilibrium (LD) in 2 eco- nomically important Sicilian local cattle breeds, Cinisara (CIN) and Modicana (MOD), using the Illumina Bovine SNP50K v2 BeadChip. To understand the genetic rela- tionship and to place both Sicilian breeds in a global context, genotypes from 134 other domesticated bovid breeds were used. Principal component analysis showed that…

RAPD variation within and among natural populations of outcrossing willow-leaved foxglove (Digitalis obscura L.)

1999

Random amplified polymorphic DNA (RAPD) markers were used to assess levels and patterns of genetic diversity in Digitalis obscura L. (Scrophulariaceae), an outcrossing cardenolide-producing medicinal plant species. A total of 50 plants from six natural populations on the Iberian Peninsula were analysed by six arbitrarily chosen decamer primers resulting in 96 highly reproducible RAPD bands. To avoid bias in parameter estimation, analyses of population genetic structure were restricted to bands (35 of 96) whose observed frequencies were less than 1–3/n in each population. The analysis of molecular variance (AMOVA) with distances among individuals corrected for the dominant nature of RAPDs (g…

2015

Small and isolated populations usually exhibit low levels of genetic variability, and thus, they are expected to have a lower capacity to adapt to changes in environmental conditions, such as exposure to pathogens and parasites. Comparing the genetic variability of selectively neutral versus functional loci allows one to assess the evolutionary history of populations and their future evolutionary potential. The genes of the major histocompatibility complex (MHC) control immune recognition of parasites, and their unusually high diversity is genes which is likely driven by parasite-mediated balancing selection. Here, we examined diversity and differentiation of neutral microsatellite loci and…

Genetic diversity and clonal variation within the main Sicilian olive cultivars based on morphological traits and microsatellite markers

2014

The richness of Olea europaea (L.) genetic resources in Sicily is well documented. In the last 30 years, mostof the local cultivars, landraces and ecotypes have been gathered together in a large ex-situ collection,containing more than 300 genotypes. In this study, 45 putative clones of the main Sicilian olive cultivarswere characterized morphologically using microsatellite markers to unambiguously identify possiblesuperior genotypes. The microsatellites employed were polymorphic (observed heterozygosity = 0.71;polymorphic information content = 0.59), discriminated 52% of the genotypes and enabled the detectionof intra-cultivar polymorphism, derived from both somatic mutations, indicating th…

Chimerism and genetic diversity within the cultivar group of pinots

2002

Three clones of Vitis vinifera cv. pinot gris were analysed at 50 microsatellite loci to assess the presence of intra-varietal genetic variability. Two clones revealed a polymorphism expressed by the presence of three alleles at 5 loci instead of the two expected for a diploid species. By sequencing the three alleles amplified at two loci, we confirm that they correspond to different allelic states of the same locus but differ in their number of repeat units. Such tri-allelic profiles could reveal periclinal chimeras in which the two cell layers of the apical meristem are genetically different. For two clones, this periclinal chimeric state has been deduced from the comparison of the genoty…

Genome-wide analysis identifies potentially causative genes explaining the phenotypic variability in Pinzirita sheep

2019

Genome-wide analysis identifies potentially causative genes explaining the phenotypic variability in Pinzirita sheep

Congruence in genetic markers used to describe Mediterranean and Atlantic populations of European hake (Merluccius merluccius L. 1758)

2004

Summary Eight samples of the hake, Merluccius merluccius L., from the Mediterranean basin (370 fishes total) and one from the Atlantic ocean (50 fishes) were analysed in order to assess genetic variability and describe genetic population structure. Five polymorphic protein coding loci were scored (ADH*, PGI-1*, PGI-2*, PGM* and SOD-1*) in eight samples, together with a haplotype variation of four samples, obtained from polymerase chain reaction/restriction fragment length polymorphism (PCR–RFLP) analysis on the mitochondrial DNA control region. The average value for observed heterozygosity was typically higher than expected (showing an excess of heterozygotes among the samples) whereas the …

Lack of seasonal changes in mitochondrial DNA variability of a Drosophila subobscura population

1994

Restriction site analysis of mtDNA of 550 isofemale lines corresponding to different seasonal samples of a single geographic population of Drosophila subobscura was carried out. The distribution pattern of haplotypes was similar to that observed for the entire range of the species on the European continent: two haplotypes were equally and highly frequent, and a set of sporadic haplotypes were almost never present in more than one seasonal sampling. No statistically significant evidence was found for between-population heterogeneity across time, and the mean within-population variation was similar to other mtDNA restriction site analyses previously reported for D. subobscura populations. The…

Intraclonal variation in RNA viruses: generation, maintenance and consequences

2003

This paper explores the evolutionary implications of the enormous variability that characterizes populations of RNA viruses and retroviruses. It begins by examining the magnitude of genetic variation in both natural and experimental populations. In natural populations, differences arise even within individual infected patients, with the per-site nucleotide diversity at this level ranging from <1% to 6%. In laboratory populations, two viruses sampled from the same clone differed by ∼0.7% in their fitness. Three different mechanisms that may be important in maintaining viral genetic variability were tested: (1) Fisher's fundamental theorem, to compare the observed rate of fitness change with …