genetic erosion
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2021 ◽  
Vol 37 ◽  
pp. e37092
Author(s):  
Jaílson Do Nascimento Silva ◽  
João Paulo Gomes Viana ◽  
Marcones Ferreira Costa ◽  
Gisele Holanda de Sá ◽  
Maria Fernanda da Costa Gomes ◽  
...  

“Sucupira branca” is a plant found in the Brazilian Cerrado and is adapted to low fertility soils, and its fruit extract has anti-inflammatory, healing, antiulcerogenic, antimicrobial, cercaricidal, leishmanicidal and antioxidant activities. Furthermore, it provides protection against oxidative stress, is a natural biocontrol agent of Aedes aegypti, has very resistant wood, is a melliferous plant and has been used in reforestation programs. The development of conservation strategies is important for maintaining diversity in natural populations of “sucupira branca” since these populations are in the process of genetic erosion. Molecular biology techniques, which are important for characterizing the genetic diversity of plants to develop conservation strategies, require sufficient high-quality genomic deoxyribonucleic acid (DNA). This study aimed to compare five methods to extract DNA from “sucupira branca”. The quality and concentration of DNA were revealed by agarose gel electrophoresis, and only the protocols of Dellaporta, Wood and Hicks et al. (1983) and Khanuja et al. (1999) did not result in satisfactory quantities of DNA. When PCR (Polymerase Chain Reaction) was performed with three inter-simple sequence repeat (ISSR) primers, DNA was successfully amplified from extractions performed with the protocols proposed by Doyle and Doyle (1987), Romano and Brasileiro (1998) and Ferreira and Grattapaglia (1995), which are less expensive than commercial purification kits. These protocols resulted in DNA of sufficient quality and quantity after the amplification reactions were performed.


2021 ◽  
Vol 2 (4) ◽  
pp. 66-71
Author(s):  
Alemayehu Zemede Lemma ◽  
Firew Mekbib ◽  
Kebebew Assefa Abebe ◽  
Zewdie Bishaw

The demand and use of improved crop varieties by farmers has increased in the central highlands of Ethiopia, where continuous loss of local traditional varieties has been occurring in the last two to three decades. The objectives of the study were to assess the extent of genetic erosion and perception of farmers and associated causes for the reduction of traditional farmers' varieties. Direct field assessment covering 56 wheat farms and a survey in which 149 farmers participated were carried out in three districts of central Ethiopia. Based on data collected during direct farm assessment, the loss of genotypes was found to be 88% in Ada followed by 80% and 60% in Lume and Gimbichu districts, respectively. The farmer survey indicated an even greater loss of diversity of100% in Ada followed by Lume (93%) and Gimbichu (67%). Diseases and pests as well as shorter growing seasons associated with climate change were identified as main causes for farmers to switch to modern varieties. The expansion of high yielding improved bread and durum wheat varieties also contributed to gradually replace local durum wheat varieties by local farmers of these districts. Overall, genetic erosion of tetraploid wheat varied among the three districts of central Ethiopia. Reductions in the number of farmers and area coverage in the study districts could be used as good indicators for the existence of genetic erosion.


2021 ◽  
Author(s):  
Renu Suyal ◽  
Arun K. Jugran ◽  
Indra D. Bhatt ◽  
Ranbeer S. Rawal

Abstract Polygonatum cirrhifolium is an important medicinal herb of family Asparagaceae used to cure several ailments. Its rhizome forms an important ingredient of “Chyavanprash” which is identified for its rejuvenating properties. However, P.cirrhifolium is least explored scientifically and systematically till date. Therefore, in this study genetic diversity and phytochemical variations along with antimutagenic activity of P.cirrhifolium populations was evaluated. Antimutagenic activity varied remarkably (p<0.05) having Gagar population with significantly (p<0.05) higher DNA recovery (84.95%) percentage. Higher genetic diversity (He) was recorded among populations using RAPD (He, 0.30-0.36) and ISSR (0.25-0.38) markers. High intra and low inter population variations were recorded in the species using both kinds of markers. Phenolics (p<0.05; r=0.924); tannins (p<0.05; r=0.897) and DNA damage inhibition efficiency displayed a highly positive correlation with genetic diversity (estimated using ISSR markers). The population structure analysis of P. cirrhifolium revealed that the greatest value of the K was 3 for studied populations. Gene flow among studied populations was found sufficient to encounter genetic erosion in the species. Therefore, it can be recommended that the populations with higher ingredient and genetic diversity can be utilized for conservation priority and management plan of this species.


2021 ◽  
Author(s):  
Tianying Lan ◽  
Kalle Leppala ◽  
Crystal Tomlin ◽  
Sandra L Talbot ◽  
George K Sage ◽  
...  

The polar bear (Ursus maritimus) has become a symbol of the threat to biodiversity from climate change. Understanding polar bear evolutionary history may provide insights into apex carnivore responses and prospects during periods of extreme environmental perturbations. In recent years, genomic studies have examined bear speciation and population history, including evidence for ancient admixture between polar bears and brown bears (Ursus arctos). Here, we extend our earlier studies of a 130,000-115,000-year-old polar bear from the Svalbard Archipelago using 10X coverage genome sequence and ten new genomes of polar and brown bears from contemporary zones of overlap in northern Alaska. We demonstrate a dramatic decline in effective population size for this ancient polar bear's lineage, followed by a modest increase just before its demise. A slightly higher genetic diversity in the ancient polar bear suggests a severe genetic erosion over a prolonged bottleneck in modern polar bears. Statistical fitting of data to alternative admixture graph scenarios favors at least one ancient introgression event from brown bears into the ancestor of polar bears, possibly dating back over 150,000 years. Gene flow was likely bidirectional, but allelic transfer from brown into polar bear is the strongest detected signal, which contrasts with other published works. These findings have implications for our understanding of climate change impacts: polar bears, a specialist Arctic lineage, may not only have undergone severe genetic bottlenecks, but also been the recipient of generalist, boreal genetic variants from brown bear during critical phases of Northern Hemisphere glacial oscillations.


2021 ◽  
Vol 4 ◽  
pp. 1-7
Author(s):  
Teresa Amodio

Abstract. This research studies the protection of the rural landscape and agri-food heritage, offering a perspective on the role and contribution of research to support land management processes and the development of local resources.This opportunity for reflection was created by a project developed at the request of Regione Campania, in Southern Italy, aimed at preserving the inestimable source of biodiversity represented by olive varieties from the risk of genetic erosion, and at guaranteeing the production of oils with typical and diversified organoleptic qualities and properties.Within the scope of the project, the geo-cartographic section has analyzed, surveyed, georeferenced and represented, for a selected territory, the presence of centuries-old olive trees and allowed the creation of other research sections, more specifically agronomic and legal.The georeferencing map of the millenary olive trees typical of the territory, together with the genetic identity card of each plant, have been inserted in a publicly accessible database, through which it is possible to trace the origins and, consequently, the quality of the oil produced.


2021 ◽  
Vol 20 (1) ◽  
pp. 1-11
Author(s):  
S.O. DUROSARO ◽  
B.T. OSHINOWO ◽  
A.C. AKPOJO ◽  
L.T. OLUYOMBO ◽  
I.C. NWOSU ◽  
...  

Nigerian indigenous chickens possess immunity from endemic diseases and have a better survival rate than commercial hybrid strains under local production conditions. FUNAAB Alpha chicken was developed by improving Nigerian indigenous chickens through crossbreeding and selection. This study compared the mitochondrial d-loop of FUNAAB Alpha and Nigerian indigenous chickens to check likely genetic erosion and loss of diversity in development of FUNAAB Alpha breed. Blood samples were collected from Nigerian indigenous (n=23) and FUNAAB Alpha (n=20) chickens sampled from farms and houses in Ogun state, Nigeria. The Hypervariable 1 (HV1) of the mitochondrial d-loop region was amplified and sequenced. Single nucleotide polymorphisms present in HV1 of chickens were identified using Clustal W. Genetic diversity of the region was determined using DnaSp v5 while selective forces acting on the chickens were predicted using HyPhy software implemented inside MEGA 6 software. Phylogenetic relationship among FUNAAB Alpha, Nigerian indigenous and other chicken breeds was determined using MEGA 6 software. Five polymorphisms were identified in FUNAAB Alpha chickens while twelve were identified in Nigerian indigenous chickens. All the polymorphisms identified in FUNAAB Alpha chickens were also observed in Nigerian indigenous chickens while seven polymorphisms were unique to Nigerian indigenous chickens. Higher diversity indices were observed in Nigerian indigenous chickens (number of haplotype: 4; haplotype diversity: 0.743±0.012; nucleotide diversity: 0.014±0.0013 and average number of nucleotide differences: 4.332) compared with FUNAAB Alpha chickens (number of haplotype: 2; haplotype diversity: 0.485±0.001; nucleotide diversity: 0.008±0.0001 and average number of nucleotide differences: 2.424). Positive selective forces were acting on FUNAAB Alpha chickens while negative selective forces were acting on Nigerian indigenous chickens. Phylogenetic analysis revealed that FUNAAB Alpha chickens clustered with Nigerian indigenous and South American chickens. It can be concluded that there was likely genetic erosion and loss of diversity in development of FUNAAB Alpha breed. Breeding programmes aimed at improvement of genetic diversity and reduction of genetic erosion should be applied in subsequent improvement of FUNAAB Alpha chickens.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Fekadu Gadissa ◽  
Meskerem Abebe ◽  
Tesfaye Bekele

Abstract Background Cultivated barley (Hordeum vulgare L.) is one of the world’s important cereal crops. Ethiopia is claimed to be the centre of origin due to its high phenotypic diversity and flavonoid patterns. It is widely cultivated on subsistence bases and important in supporting the livelihood of local poor. However, the local landraces are currently under threat of severing genetic erosion. Hence, assessing the extents of its genetic diversity is timely in improvement and conservation. Methodology 120 representative cultivated barley landraces have been collected from Bale highlands, Ethiopia, and tested at two locations using alpha lattice design. Data were collected on 21 agro-morphometric traits and analysed using MINITAB 19, SAS 9.4 and FigTree v1.4.3. Results Most morphotypes in each of the qualitative traits considered and mean performance values in most of the quantitative traits revealed wide range of variations suggesting existence of phenotypic diversity among the landraces. Analysis of variance also showed significant variations among the landraces. All the traits, except days to maturity and plant height showed a significant variation for location and treatment-location interactions revealing the high impact of environmental conditions on the variations. Estimates of the variance components also revealed a wider range of variations in most of the traits considered with eventual medium to low genotypic (GCV), phenotypic (PCV) and genotype–environment coefficients of variation (GECV). Estimates of heritability in broad sense (H2) is low (< 40%) in all the traits except in days to maturity. Grouping of the landraces showed poor geographic areas of collection-based pattern suggesting extensive gene flow among the areas. Conclusion The landraces evaluated in the present study showed high morphological diversity. However, the effect of environment factor is pronounced and thus, multiple locations and years with large number of samples must be considered to exploit the available genetic-based variations for breeding and conservation of the crop.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
András Cseh ◽  
Péter Poczai ◽  
Tibor Kiss ◽  
Krisztina Balla ◽  
Zita Berki ◽  
...  

AbstractHistorical wheat landraces are rich sources of genetic diversity offering untapped reservoirs for broadening the genetic base of modern varieties. Using a 20K SNP array, we investigated the accessible genetic diversity in a Central European bread wheat landrace collection with great drought, heat stress tolerance and higher tillering capacity. We discovered distinct differences in the number of average polymorphisms between landraces and modern wheat cultivars, and identified a set of novel rare alleles present at low frequencies in the landrace collection. The detected polymorphisms were unevenly distributed along the wheat genome, and polymorphic markers co-localized with genes of great agronomic importance. The geographical distribution of the inferred Bayesian clustering revealed six genetically homogenous ancestral groups among the collection, where the Central European core bared an admixed background originating from four ancestral groups. We evaluated the effective population sizes (Ne) of the Central European collection and assessed changes in diversity over time, which revealed a dramatic ~ 97% genetic erosion between 1955 and 2015.


2021 ◽  
Author(s):  
GNAPI Diane Estelle ◽  
Desire POKOU ◽  
LEGNATE Hyacinthe ◽  
DAPENG Zhang ◽  
Christophe MONTAGNON ◽  
...  

Abstract Canephora coffee is an important source of income and employment, contributing significantly to the economies of many developing countries. This species is split into two genetic groups: Guinean and Congolese. Côte-d’Ivoire is the primary diversification center of the Guinean pool, which offers great potential for genetic improvement. However, genetic erosion of this group is currently a threat in this country because of the massive introduction of Congolese accessions in the previous decades. In this work, we analyzed the progenies of isolated population of C. canephora composed of a mix of Guinean and Congolese using SNP markers. The analysis is focus on the male parents’ contribution on open pollination progenies. The result shows that the introduction of cultivars from the Congolese gene pool threat the genetic integrity of wild populations of the Guinean gene pool. We recommend that a conservation program be put in place to ensure the entegrity of wild population of C. canephora through in situ or ex situ conservation.


Agriculture ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1102
Author(s):  
Giorgia Capasso ◽  
Giorgia Santini ◽  
Mariagioia Petraretti ◽  
Sergio Esposito ◽  
Simone Landi

Barley (Hordeum vulgare L.) is one of the main crops cultivated all over the world. As for other cereals, throughout the centuries barley was subjected by human breeding to genetic erosion phenomena, which guaranteed improved yields in organized (and then mechanized) agriculture; on the other hand, this selection weakened the ability of barley to survive under adverse environments. Currently, it is clear that climate change requires an urgent availability of crop varieties able to grow under stress conditions, namely limited irrigation, salinity, high temperatures, and other stresses. In this context, an important role could be played by wild relatives and landraces selected by farmers, particularly in specific field areas and/or climatic conditions. In this review, we investigated the origin of barley and the potentialities of wild varieties and landraces in different contexts, and their resilience to abiotic stress. The data obtained from Next Generation Sequencing technologies were examined to highlight the critical aspects of barley evolution and the most important features for abiotic stress tolerance. Furthermore, the potential of appropriate mycorrhiza is discussed under the view of the essential role played by these symbioses in field crops. The abilities of specific barley wild varieties and landraces may represent novel opportunities and suggest innovative strategies for the improvement of abiotic tolerance in crops and particularly in barley.


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