Impact de la sélection sur la variabilité génétique de l'épinette blanche au Québec

1993 ◽  
Vol 23 (6) ◽  
pp. 1196-1202 ◽  
Author(s):  
Mireille Desponts ◽  
Ariane Plourde ◽  
Jean Beaulieu ◽  
Gaétan Daoust
Keyword(s):  
Genetic Structure ◽  
Natural Populations ◽  
Diallel Cross ◽  
Significant Loss ◽  
Enzymatic Systems ◽  
Old Trees ◽  
Number Of Individuals ◽  
Very High ◽  
Sizeable Reduction ◽  
Selection Of

The genetic structure and variability of two natural white spruce (Piceaglauca (Moench) Voss.) populations from southern Quebec were compared by isoenzymatic analysis with those observed from three superior provenances of the Great Lakes and St. Lawrence regions. Twenty 15- to 20-year-old trees, selected within the provenances and integrated into a diallel cross plan, were also studied. The analysis of seven enzymatic systems demonstrates, in an overall fashion, the consistency of variability within provenances when these are compared with natural populations. It indicates that the selection of a restricted number of individuals in these populations does not cause a significant loss of variability. The level of heterozygosity for the selected individuals integrated into the diallel cross plan appears very high and no loss of alleles is recorded when compared with the original provenances, despite the sizeable reduction in numbers. This result suggests that the second selection, in favour of individuals demonstrating a strengthened vigour, favored the most polymorph genotypes.

scholarly journals Leucotelium cerasi (Bérenger) Tranzschel 1935, novel pathogen for mycobiota in Serbia

2020 ◽  
pp. 29-38
Author(s):  
Stefan Bogosavljevic ◽  
Milos Stupar ◽  
Milica Ljaljevic-Grbic ◽  
Jelena Vukojevic
Keyword(s):  
Host Species ◽  
Natural Populations ◽  
Field Studies ◽  
Parasitic Fungus ◽  
Prunus Species ◽  
Protection Measures ◽  
Foliar Tissue ◽  
High Degree ◽  
Number Of Individuals ◽  
Very High

During the field studies on a strictly protected plant species Eranthis hyemalis (winter aconite) in Serbia, it was noticed that certain individuals were infected by some species of parasitic fungus. According to the structure of spermogonia and aecia, as well as distinctive types of spores recorded in infected leaves of winter aconite, the fungus was determined as Leucotelium cerasi, known as a causative agent of rust in E. hyemalis and Prunus species. Although it was first recorded in Serbia in Prunus spinosa as a host (area of Valjevo in 1935), the appearance of this phytopathogen was recorded in foliar tissue of E. hyemalis at four localities in Eastern Serbia, near Knjazevac (Podvis, Golemi Kamen, and Ploca) and Zajecar (Zmijanac). It was concluded that plants in natural populations of host species were infected to a very high degree, as the number of infected plants reached half of the total number of individuals in all studied populations. Further research is neces?sary to determine to what extent this fungus is threatening the survival of host populations and then implement appropriate protection measures.

Der Sommer und Herbst 2003 aus phänologischer Sicht | Summer and autumn 2003 from a phenological point of view

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Time Series ◽  
New Record ◽  
Point Of View ◽  
Late Spring ◽  
Mean Deviation ◽  
Leaf Shedding ◽  
The Mean ◽  
Very High ◽  
Selection Of

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.

Failed predation in Late Ordovician gastropods (Mollusca) from Manitoulin Island, Ontario, CanadaThis article is one of a selection of papers published in this Special Issue on the theme The dynamic reef and shelly communities of the Paleozoic. This Special is in honour of our colleague and friend Paul Copper.

2008 ◽  
Vol 45 (2) ◽  
pp. 231-241 ◽  
Author(s):  
Jan Ove R. Ebbestad ◽  
Christopher A. Stott
Keyword(s):  
Success Rate ◽  
Late Ordovician ◽  
Size Class ◽  
Low Energy ◽  
Special Issue ◽  
Georgian Bay ◽  
Low Level ◽  
Shell Repair ◽  
Number Of Individuals ◽  
Selection Of

Shell repairs resulting from presumed failed predation are documented in gastropods from the Late Ordovician (Cincinnatian; Richmondian) mid-to-upper Kagawong Submember of the Georgian Bay Formation on Manitoulin Island, Ontario, Canada. The bryozoan–mollusc biota and associated sediments generally suggest nearshore, shallow (<10 m), low energy (lagoonal), and perhaps mesotrophic to eutrophic conditions. Two sample sets from this unit have been studied for shell repair. One of the more commonly applied estimates of shell repair frequencies involves division of the number of individuals with at least one scar by the total number of individuals in the sample (the Individuals with scars method). Using this calculation, 207 specimens of Lophospira trilineata Ulrich and Scofield yielded a shell repair frequency of 4.8%; in 28 specimens of Trochonemella sp. the shell repair frequency was 35.7%. Repairs in Trochonemella occur primarily in the larger size class, suggesting that a size refuge was achieved by this species. Low repair frequencies in L. trilineata suggest predation with a higher success rate or fewer encounters. This study demonstrates that the paradigm of a standardized low level of shell repair in Ordovician and Silurian gastropods is oversimplistic and a range of frequency rates can be expected.

scholarly journals Genetic variation in the dietary sucrose modulation of enzyme activities in Drosophila melanogaster

1984 ◽  
Vol 43 (3) ◽  
pp. 307-321 ◽  
Author(s):  
Billy W. Geer ◽  
Cathy C. Laurie-Ahlberg
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Enzyme Activities ◽  
Glycogen Synthesis ◽  
Krebs Cycle ◽  
Natural Populations ◽  
Substitution Lines ◽  
Chromosome Substitution Lines ◽  
High Sucrose Diet ◽  
Selection Of

SUMMARYGenetic variation in the modulating effect of dietary sucrose was assessed in Drosophila melanogaster by examining 27 chromosome substitution lines coisogenic for the X and second chromosomes and possessing different third isogenic chromosomes derived from natural populations. An increase in the concentration of sucrose from 0·1% to 5% in modified Sang's medium C significantly altered the activities of 11 of 15 enzyme activities in third instar larvae, indicating that dietary sucrose modulates many, but not all, of the enzymes of D. melanogaster. A high sucrose diet promoted high activities of enzymes associated with lipid and glycogen synthesis and low activities of enzymes of the glycolytic and Krebs cycle pathways, reflecting the physiological requirements of the animal. Analyses of variance revealed significant genetic variation in the degrees to which sucrose modulated several enzyme activities. Analysis of correlations revealed some relationships between enzymes in the genetic effects on the modulation process. These observations suggest that adaptive evolutionary change may depend in part on the selection of enzyme activity modifiers that are distributed throughout the genome.

Population genetic structure and dispersal of Pinus occidentalis in the Dominican Republic by chloroplastic SSR with implications for its conservation, management, and reforestation

2021 ◽  
Author(s):  
Luis E. Rodríguez de Francisco ◽  
Rosanna Carreras-De León ◽  
Rafael M. Navarro Cerrillo ◽  
Liz A. Paulino-Gervacio ◽  
María-Dolores Rey ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Dominican Republic ◽  
Population Genetic Structure ◽  
Population Genetic ◽  
Conservation Management ◽  
Natural Populations ◽  
Limited Information ◽  
High Genetic Diversity ◽  
The Impact ◽  
Pinus Occidentalis

<i>Pinus occidentalis</i> is the dominant species of forest ecosystems in the Dominican Republic, located between 200 and 3000 meters above sea level, with extensive and overexploited natural populations. However, over the years, various restoration plans have been performed, which could affect the genetic structure of <i>P. occidentalis</i>. Despite being the species with the highest occurrence in the Dominican forests, there is no existing information on genetic structure and molecular characterization among natural populations with limited information on both phenological and productive characterization. In this study, the genetic structure, diversity, and gene flow of the five <i>P. occidentalis</i> natural populations of the Dominican Republic were determined using microsatellite markers. A total of 145 individuals were genotyped with eight polymorphic chloroplastic microsatellites, producing an average of 41 haplotypes with high genetic diversity across populations (H<sub>E</sub> = 0.90). Significant population genetic structure was found between populations (F<sub>ST</sub> = 0.123). These results reflect the impact of reforestation programs on natural populations and diluting the natural genetic signature. Analysis of population genetic data is, therefore, crucial for the breeding and conservation programs of <i>P. occidentalis</i> in the country.

PSXII-2 Identification of candidate SNPs associated with high prolificacy in Romanov sheep

2021 ◽  
Vol 99 (Supplement_3) ◽  
pp. 254-255
Author(s):  
Alexey V Shakhin ◽  
Arsen V Dotsev ◽  
Tatiana E Deniskova ◽  
Gottfried Brem ◽  
Natalia A Zinovieva
Keyword(s):  
Higher Education ◽  
Genetic Basis ◽  
Reference Genome ◽  
Unique Property ◽  
Candidate Snps ◽  
Merino Sheep ◽  
Sheep Breeds ◽  
Important Trait ◽  
Very High ◽  
Selection Of

Abstract Prolificacy is a very important trait in sheep. Romanov sheep, the well-known Russian sheep breed, are characterized by very high prolificacy; however, the genetic basis of this unique property of Romanov sheep is still unknown. It was reported that Ovine BMPR1B gene, located on the OAR6, is associated with prolificacy in several sheep breeds. The aim of our study was to identify candidate SNPs within BMPR1B gene, related to prolificacy. To achieve this goal, using NGS technology, we sequenced ovine BMPR1B gene in Romanov sheep (n = 6), which are characterized by high prolificacy (about 270 lambs per 100 ewes). The sequences of BMPR1B gene of Noire du Velay, Tan, Southdown and Australian Horned Merino sheep breeds as well as Asiatic mouflon (n = 1), which are characterized by significantly lower prolificacy (from 110 to 180 lambs per 100 ewes) were derived from publicly available sources and used for comparison. FST analysis performed in PLINK 1.9 program revealed 10 SNPs with values higher than 0.8. The majority of candidate SNPs under putative selection were localized in the region from 29,382,098 to 29,430,387 on OAR6 of Ovine reference genome (Oar_v3.1 (Ensembl release 98). Thus, we can suggest, that this region of the BMPR1B gene can be considered as the putative region, associated with high prolificacy of Romanov sheep. Additional studies will be needed to confirm the effect of identified candidate SNPs on prolificacy traits. The research results will be useful for artificial selection of sheep with higher prolific capacity, including the introduction of desired alleles in sheep populations using genome editing technologies. This work was supported by the Russian Ministry of Science and Higher Education No. 0445-2019-0024 and RFBR No. 20-516-56002.

Sign in / Sign up

Export Citation Format

Share Document