scholarly journals Genetic evaluation of seeds of highly endangered Pinus uliginosa Neumann from Węgliniec reserve for ex-situ conservation program

2011 ◽  
Vol 74 (3) ◽  
pp. 237-242 ◽  
Author(s):  
Andrzej Lewandowski ◽  
Jarosław Burczyk ◽  
Witold Wachowiak ◽  
Adam Boratyński ◽  
Wiesław Prus-Głowacki
Keyword(s):  
Genetic Variation ◽  
Genetic Erosion ◽  
Minimum Variance ◽  
Ex Situ ◽  
The Mean ◽  
Low Levels ◽  
Species Specific ◽  
High Level ◽  
Individual Trees ◽  
Pinus Uliginosa

Peat-bog pine <em>Pinus uliginosa</em> Neumann has become extinct or rare in many parts of Europe. We have investigated the levels of genetic variation and inbreeding in seeds collected from a highly endangered reserve of this species in Poland, using allozymes as genetic markers. Generally, a high level of genetic variation was observed. The mean expected heterozygosity was 0.376, while average (Na) and effective (Ne) numbers of alleles per locus were 2.45 and 1.67, respectively. Nevertheless, we have detected relatively low levels of outcrossing, and potential biparental inbreeding. The population-wide multilocus outcrossing rate was estimated to be 0.706 (±0.091), while the minimum variance mean of single-locus estimates was distinctly lower (ts=0.611). The estimates of outcrossing calculated for individual trees ranged widely from 0.051 to 1.017, indicating the complexity of outcrossing patterns. The investigated population of <em>P. uliginasa</em> from Węgliniec is small and surrounded by extensive forest stands of <em>P. sylvestris</em>. Our three-year records of phenological observations demonstrated that flowering periods for <em>P. uliginosa</em> and <em>P. sylvestris</em> overlap, allowing for cross-pollination. The possibility of <em>P. uliginosa</em> pollination by <em>P. sylvestris</em> creates a potential danger of genetic erosion of the <em>P. uliginosa</em> gene pool. Nonetheless, based on a species specific cpDNA marker we have found that among 533 seedlings of <em>P. uliginosa</em> there were only six seedlings carrying cpDNA marker specific for <em>P. sylvestris</em>, indicating that such hybridization seems to be rare.

Low levels of outcrossing in Pinus leucodermis: further evidence in artificial stands

1994 ◽  
Vol 72 (9) ◽  
pp. 1289-1293 ◽  
Author(s):  
M. Morgante ◽  
P. Rossi ◽  
G. G. Vendramin ◽  
G. Boscherini
Keyword(s):  
Natural Populations ◽  
Selective Advantage ◽  
Minimum Variance ◽  
Outcrossing Rates ◽  
Self Fertilization ◽  
Low Levels ◽  
High Level ◽  
Germinating Seeds ◽  
Neighbourhood Structure ◽  
Key Words Mating System

Outcrossing rates were estimated in two artificial stands of Pinus leucodermis, a wind pollinated conifer characterized by a relatively high level of selfing. Multilocus outcrossing rates, estimated by assaying five enzyme loci, were lower than 86% in the two stands, using both dormant and germinating seeds, and not different from those observed in two natural populations located in the same area. The lack of relevant differences between single-locus minimum variance means and the multilocus outcrossing rate estimates observed in both the artificial stands indicates that most of the apparent selfing is probably caused by actual self-fertilization. The presence of a high level of self-fertilization in this species seems confirmed also in artificial stands, where the density is higher and neighbourhood structure should be less pronounced. The high level of self-fertilization found in P. leucodermis, which is probably due to the presence of a reduced number of recessive embryonic lethals as a consequence of genetic drift, could represent a selective advantage for this pioneering and precocius species. Key words: mating system, outcrossing rates, artificial stands, Pinus leucodermis.

The influence of selection and plane of nutrition on the components of fleece weight in Merino sheep

1958 ◽  
Vol 9 (6) ◽  
pp. 802 ◽  
Author(s):  
RB Dun
Keyword(s):  
Fibre Diameter ◽  
Fibre Length ◽  
Small Contribution ◽  
Cross Sectional ◽  
Single Character ◽  
The Mean ◽  
Low Levels ◽  
The Difference ◽  
Fleece Weight ◽  
High Level

The components of clean fleece weight were examined in five experimental flocks of medium-wool Peppin Merinos. Four single-character selection groups – clean fleece weight plus, clean fleece weight minus, crimps per inch plus, and crimps per inch minus – were examined by measuring fleece production in 18-month-old ewe progeny. Measurements were also made on progeny from the "nucleus" flock, which was selected for clean fleece weight with subsidiary selection for crimps per inch and against fold score. Data were collected in 1952 and 1954. The 1954 figures were obtained from a nutrition experiment in which sheep mere grown from weaning to 18 months on a high and on a low plane of nutrition. The mean measurements of the components of clean fleece weight (W) were compared between flocks using the "percentage deviation" technique. Four comparisons were made: (1) Nucleus/Fleece minus; (2) Fleece plus/Fleece minus; (3) Crimps minus/Crimps plus; (4) high nutritional plane/low nutritional plane. In comparisons (1) , (2), and (3), difference in weight of wool per unit area of skin (w) accounted for nearly all the difference in W. Body weight (S) made a small contribution while difference in fold score (R) was negligible. Fibre density (N) accounted for +86 per cent., and fibre cross-sectional area (A) for –28 per cent., of the difference in W in comparison (1). In comparison (2) the figures were N +47 per cent., A +21 per cent., while the figures for comparison (3) were N –26 per cent., A +121 per cent. The increase in fleece weight was invariably accompanied by a decrease in crimps per inch. In all three comparisons primary density (P) was the major cause of change in N. Fibre length (L) made a uniform contribution of approximately +15 per cent. in the three comparisons.The relative importance of the components of fleece weight was similar at both high and low levels of nutrition.The effect of a high level of nutrition was to produce large increases in A, L, and S. The increase in S was compensated by an equal decrease in P. The increase in fibre diameter was not associated with any change in crimps per inch.

High Levels of Genetic Variability in an Isolated Colony of Rock-wallabies (Petrogale assimilis): Evidence from Three Classes of Molecular Markers

1997 ◽  
Vol 45 (2) ◽  
pp. 199 ◽  
Author(s):  
Peter B. S. Spencer ◽  
Mark Adams ◽  
Helene Marsh ◽  
David J. Miller ◽  
Mark D. B. Eldridge
Keyword(s):  
Genetic Variation ◽  
Molecular Markers ◽  
Genetic Variability ◽  
Mating Systems ◽  
Selective Pressure ◽  
Multiple Mating ◽  
Dna Fingerprints ◽  
Average Heterozygosity ◽  
Low Levels ◽  
High Level

Estimates of genetic variation for a small (Ne = 39) colony of allied rock-wallabies (Petrogale assimilis) were calculated with three different categories of molecular marker. Average heterozygosity was estimated at 3·8% for allozymes, 47·3% for multilocus ‘DNA fingerprints’ and 85·5% for microsatellite markers. Overall these values indicate that this small isolated colony of rock-wallabies maintains a high level of genetic variation despite its relative isolation and the apparently low levels of migration between colonies. It is likely that mechanisms exist (such as kin avoidance, multiple mating systems, high and variable selective pressure in extreme and fluctuating environmental conditions) that promote the maintenance of high levels of genetic variation in isolated colonies of P. assimilis. These mechanisms are discussed in the context of the results obtained from the molecular markers.

Genetic variation within and among populations of Camelliajaponica (Theaceae) in Korea

1996 ◽  
Vol 26 (4) ◽  
pp. 537-542 ◽  
Author(s):  
Myong Gi Chung ◽  
Soon Suk Kang
Keyword(s):  
Genetic Diversity ◽  
Genetic Variation ◽  
Pollen Dispersal ◽  
Island Populations ◽  
Generation Times ◽  
Genetic Diversity And Structure ◽  
Stump Sprouting ◽  
Ability To Regenerate ◽  
The Mean ◽  
High Level

The genetic diversity and structure of 17 Korean populations of Camelliajaponica L., a broad-leaved evergreen tree, was examined. Although most populations are restricted to several islands near the southern and southwestern coast of the Korean Peninsula, they maintain higher levels of genetic variation within populations than do long-lived, woody angiosperms. For example, 13 of 16 loci examined were polymorphic in at least one population, the mean number of alleles per locus was 2.63, and mean expected heterozygosity was 0.265. These values were comparable with those for continuously distributed, mainland populations of C. japonica in Japan. However, a considerably high level of heterozygote deficiency was observed in Korean populations of C. japonica (mean FIS = 0.202). About 13% of the total genetic variation was found among populations (GST = 0.129). Indirect estimates of the number of migrants per generation (1.69, calculated from FST; 2.14, calculated from the mean frequency of eight private alleles) indicate that gene flow among island populations is moderate. Factors contributing to the high levels of genetic diversity found in the entire species of C. japonica include long generation times, ability to regenerate by stump sprouting, predominant outcrossing induced by animal vectors, and occasional pollen dispersal by birds.

scholarly journals Genetic diversity and population structure of Eurycoma apiculata in Eastern Sumatra, Indonesia

2021 ◽  
Vol 22 (10) ◽  
Author(s):  
Zulfahmi Zulfahmi ◽  
Parjanto Parjanto ◽  
Edi Purwanto ◽  
Ahmad Yunus
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
Genetic Differentiation ◽  
Gene Diversity ◽  
In Situ Conservation ◽  
Genetic Material ◽  
Ex Situ ◽  
Breeding Programs ◽  
The Mean

Abstract. Zulfahmi, Parjanto, Purwanto E, Yunus A. 2021. Genetic diversity and population structure of Eurycoma apiculata in Eastern Sumatra, Indonesia. Biodiversitas 22: 4431-4439. Information on genetic variation within and among populations of Eurycoma apiculata plants is important to develop strategies for their conservation, sustainable use, and genetic improvement. To date, no information on genetic variation within and among populations of the E. apiculata has been reported. This study aims to assess genetic diversity within and among populations of E. apiculata based on RAPD markers, and to determine populations to collect E. apiculata genetic material for conservation and breeding programs. Young leaves of E. apiculata were collected from six natural populations. Fifteen RAPD primers were used to assess the genetic diversity of each population. The data obtained were analyzed with POPGEN and Arlequin software. The amplification results of 15 selected primers produced 3-16 loci with all primers 100% polymorphic. At the species level, the mean allele per locus (Na), number of effective alleles (Ne), percentage of polymorphic loci (PPL), Nei’s gene diversity index (He) and Shannon information index (I) were 2.000, 1.244, 100%, 0.167, and 0.286, respectively. At the population level, the mean values for Na, Ne, PPL, He and I were 1.393, 1.312, 39.27%, 0.119, and 0.186, respectively. The highest value of gene diversity within population (He) was found in the Lingga-1 population and the lowest value was found in the Rumbio population. The value of genetic differentiation among populations (GST) of E. apiculata is 0.284, consistent with the results of the AMOVA analysis which found that genetic variation among populations was 23.14%, indicates that the genetic variation of E. apiculata was more stored within populations than among populations. The gene flow (Nm) value of E. apiculata was 1.259 migrants per generation among populations. The Nm value of this species was high category, and could inhibit genetic differentiation among populations. The clustering of E. apiculata population based on the UPGMA dendrogram and PCA was inconsistent with its geographic distribution, reflecting the possibility that genes migration occurred between islands in the past. The main finding of this study was the genetic variation of the E. apiculata mostly stored within the population. Therefore, the population with the highest genetic diversity is a priority for in-situ conservation, and collection of E. apiculata genetic material for ex-situ conservation and breeding programs should be carried out minimum from Lingga-1 and Pokomo populations.

scholarly journals High Level of Physical Activity Reduces the Risk of Renal Progression in Hypertensive Patients

2020 ◽  
Vol 17 (5) ◽  
pp. 1669
Author(s):  
Po-Ya Chang ◽  
Shu-Yu Lyu ◽  
Yuh-Feng Lin ◽  
Chun-Ching Huang
Keyword(s):  
Physical Activity ◽  
Odds Ratio ◽  
Estimated Glomerular Filtration Rate ◽  
Metabolic Equivalent ◽  
Hypertensive Patients ◽  
Renal Progression ◽  
The Mean ◽  
Low Levels ◽  
High Level ◽  
The Relationship

Physical activity has long been associated with chronic diseases. However, the association between physical activity and renal progression in hypertensive patients remains unclear. This study investigated the relationship between the level of physical activity and renal function in hypertensive patients. We analyzed 3543 patients with hypertension. Data on patients’ demographic characteristics, comorbidities, physical activity, and lifestyle characteristics were collected via questionnaires. An estimated glomerular filtration rate (eGFR) that was reduced by more than 25% from the baseline eGFR was defined as renal progression. This study divided physical activity into three levels (low, moderate, and high) based on their metabolic equivalent of tasks (METs) levels. The mean age was 63.32 ± 12.29 years. After we adjusted for covariates, renal progression was significantly higher among patients with low levels of physical activity (odds ratio (OR), 1.39; 95% confidence interval (CI), 1.01–1.90)) and moderate levels of physical activity (OR, 1.39; 95% CI, 1.04–1.86) than among patients with high levels of physical activity. We found a significant association between physical activity and renal progression in hypertensive patients, especially in elderly patients and men. Therefore, to reduce the risk of renal progression, we recommend that clinicians should encourage patients to improve their physical activity.

Genetic variation and population differentiation in species of Simocephalus (Cladocera, Daphniidae)

1986 ◽  
Vol 64 (10) ◽  
pp. 2246-2256 ◽  
Author(s):  
B. J. Hann ◽  
P. D. N. Hebert
Keyword(s):  
Genetic Variation ◽  
North America ◽  
Littoral Zone ◽  
Spatial Differentiation ◽  
Species Level ◽  
Evolutionary Divergence ◽  
Founder Effects ◽  
Allelic Substitution ◽  
The Mean ◽  
Low Levels

Microgeographic analysis of enzyme genetic variation in populations in the littoral zone cladoceran Simocephalus in southwestern Ontario has disclosed very low levels of intrapopulation variability. The mean percentage of polymorphic loci per population was 10.5%, and individual heterozygosity averaged less than 5% over all populations. Population structure typifies that of randomly mating, outbred sexual species. Most populations were polyclonal, with a few common widespread clones and several rarer ones, often found in only one pond. There were no significant temporal patterns in genotypic frequencies, but spatial differentiation of populations suggested that both selection and founder effects have played roles in the evolutionary divergence of these cyclic parthenogens. Despite extremely low intrapopulation and moderate intraspecific variation, there was extensive differentiation between species. As a consequence of virtually complete allelic substitution at several loci and great similarity or identity of alleles at others, diagnostic loci were detected in three of the four species. Of the four distinct clusters of populations, differentiated at the species level, three represented species previously recognized in North America (S. cf. vetulus, S. cf. serrulatus, S. cf. exspinosus), and the fourth group was identified as S. cf. congener, related to a taxon occurring in Europe, but not reported from North America. The great amount of divergence between populations of S. cf. exspinosus suggests that a complex of at least two sibling species exists within this taxon.

scholarly journals Effect of level of infection by gastrointestinal nematodes and anthelmintic treatment on milk yield in dairy sheep

Parasite ◽  
2021 ◽  
Vol 28 ◽  
pp. 71
Author(s):  
María Martínez-Valladares ◽  
Elías Martín-Ramos ◽  
Myriam Esteban-Ballesteros ◽  
Rafael Balaña-Fouce ◽  
Francisco Antonio Rojo-Vázquez
Keyword(s):  
Milk Yield ◽  
Gastrointestinal Nematode ◽  
Treated Group ◽  
Gastrointestinal Nematodes ◽  
Anthelmintic Treatment ◽  
Faecal Egg Count ◽  
Total Milk ◽  
The Mean ◽  
Low Levels ◽  
High Level

The effects of gastrointestinal nematode infections and anthelmintic treatment on milk yields was compared between flocks with a low level (LL) of eggs per gram (epg) before partum and with a high level (HL). Faecal egg count reduction tests (FECRTs) were carried out before partum comparing a treated group with netobimin with an untreated group. Ewes belonging to LL flocks produced 55.4% more milk than ewes from HL flocks. A negative correlation was found between the mean epg before treatment and the mean milk yield per flock (r = −0.860; p < 0.01). However, treated ewes produced 10.1% more milk than untreated ewes in LL flocks, although in HL flocks, treated ewes produced less milk (−2.7%). The treatment of flocks even with low levels of infection can improve the milk yields. In this study, the epg before partum had a greater influence on total milk yield than the anthelmintic treatment.

scholarly journals Blood Lead Level among school children in an Industrial city of Nepal

2017 ◽  
Vol 7 (1) ◽  
pp. 1091-1094 ◽  
Author(s):  
K Gautam ◽  
S Pradhan ◽  
V Thuppil ◽  
D Pyakurel ◽  
A Shrestha
Keyword(s):  
Blood Lead Level ◽  
Large Population ◽  
Lead Level ◽  
Blood Lead ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Industrial City ◽  
The Mean ◽  
Low Levels ◽  
High Level

Background: Widespread use of lead has caused extensive environmental contamination and health problems in many parts of the world. Children are particularly vulnerable and even relatively low levels of exposure can cause serious health conditions. Our objective was to determine the prevalence of blood lead level in children in industrial city of Nepal, Birgunj.Materials and Methods: The cross sectional study was done on 50 school going student in Birgunj city, Nepal from November 2016 to January 2017. Questionnaire was used to collect data. Capillary blood was drawn and Blood Lead Level was measured immediately. SPSS ver. 22 was used to analyze the data.Results: The mean age of children in study was 12.5 ± 1.11 years.Among 50 children, 54% were male and 46% were female. The mean blood lead level was 20.33±9.36 μg/dl (male 21.08±8.87μg/dl, female 19.46±10.92 μg/dl). All the children in the study have elevated blood lead level and 84% of them have >10 μg/dl. About 26% of children have blood lead level between 15-20 μg/dl, 12% have level 20-25 μg/dl and 4% of them have more than 35 μg/dl.Conclusion: The prevalence of blood lead level in children from the industrial city of Nepal is alarmingly high. Children exposed with chipped paints have high level of blood lead level. However, further study in large population is required to address the current situation regarding the lead exposure to children.  

scholarly journals Vulture genomes reveal molecular adaptations underlying obligate scavenging and low levels of genetic diversity

2021 ◽  
Author(s):  
Dahu Zou ◽  
Shilin Tian ◽  
Tongzuo Zhang ◽  
Nima Zhuoma ◽  
Guosheng Wu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Anthropogenic Activities ◽  
Genetic Erosion ◽  
Population Declines ◽  
Dietary Specialization ◽  
Genome Wide ◽  
The Mean ◽  
Low Levels ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Abstract Obligate scavenging on dead and decaying animal matter is a rare dietary specialization that in extant vertebrates is restricted to vultures. These birds perform essential ecological services, yet many vulture species have undergone recent steep population declines and are now endangered. To test for molecular adaptations underlying obligate scavenging in vultures, and to assess whether genomic features might have contributed to their population declines, we generated high-quality genomes of the Himalayan and bearded vultures, representing both independent origins of scavenging within the Accipitridae, alongside a sister taxon, the upland buzzard. By comparing our data to published sequences from other birds, we show that the evolution of obligate scavenging in vultures has been accompanied by widespread positive selection acting on genes underlying gastric acid production, and immunity. Moreover, we find evidence of parallel molecular evolution, with amino acid replacements shared among divergent lineages of these scavengers. Our genome-wide screens also reveal that both the Himalayan and bearded vultures exhibit low levels of genetic diversity, equating to around a half of the mean genetic diversity of other bird genomes examined. However, demographic reconstructions indicate that population declines began at around the Last Glacial Maximum, predating the well-documented dramatic declines of the past three decades. Taken together, our genomic analyses imply that vultures harbour unique adaptations for processing carrion, but that modern populations are genetically depauperate and thus especially vulnerable to further genetic erosion through anthropogenic activities.

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