Morphological and eco-geographic diversity analysis of maize germplasm in the high altitude Andes region of Ecuador

2021 ◽  
pp. 1-12
Author(s):  
César Tapia ◽  
Elena Torres ◽  
Nelly Paredes ◽  
Mauricio Parra-Quijano
Keyword(s):  
Phenotypic Diversity ◽  
Morphological Diversity ◽  
Ecological Niches ◽  
Conservation Areas ◽  
Maize Germplasm ◽  
Maize Diversity ◽  
Maize Landraces ◽  
Place Of Origin ◽  
Definition Of ◽  
Andean Highlands

Abstract The Andean region of Ecuador is the place of origin of many maize landraces grouped into 24 races. Definition of priorities for maize diversity conservation in this region can be supported by the spatial identification of areas with a high eco-geographical and phenotypic diversity. Six hundred thirty-six maize samples were morphologically characterized using 14 descriptors and assigned to a distinctive race. Additionally, sampled farms were characterized by 12 environmental variables. From these data, maps of morphological and eco-geographical diversity were obtained by using techniques to determine eco-geographical and phenotypic distances and applying them to each geographical neighbourhood. The races Patillo Ecuatoriano, Racimo de Uva and Uchima exhibited high intra-racial morphological variation, particularly in the shape of the ear, kernel row layout, cob diameter and total kernel number. The highest number of different races was observed in Imbabura, Azuay and Chimborazo provinces. The highest levels of morphological diversity were found in three cells (10 × 10 km), located in Pichincha, Chimborazo and Loja provinces. Two ecological niches, located in Loja province, showed high levels of eco-geographical diversity. A comparison between diversity maps revealed shared hotspots of morphological and eco-geographical diversity in the central and southwest areas of Imbabura province. The Andean highlands of Ecuador are an optimal refuge for the conservation of maize diversity, and the criteria of eco-geographical and morphological diversity and race richness should be considered when defining priority in situ conservation areas.

scholarly journals Defining the niche for niche construction: evolutionary and ecological niches

2021 ◽  
Vol 36 (3) ◽  
Author(s):  
Rose Trappes
Keyword(s):  
Evolutionary Biology ◽  
Ecological Niche ◽  
Niche Construction ◽  
Habitat Degradation ◽  
Ecological Niches ◽  
Niche Concept ◽  
Definition Of ◽  
Compare And Contrast ◽  
Extreme Habitat

AbstractNiche construction theory (NCT) aims to transform and unite evolutionary biology and ecology. Much of the debate about NCT has focused on construction. Less attention has been accorded to the niche: what is it, exactly, that organisms are constructing? In this paper I compare and contrast the definition of the niche used in NCT with ecological niche definitions. NCT’s concept of the evolutionary niche is defined as the sum of selection pressures affecting a population. So defined, the evolutionary niche is narrower than the ecological niche. Moreover, when contrasted with a more restricted ecological niche concept, it has a slightly different extension. I point out three kinds of cases in which the evolutionary niche does not coincide with realized ecological niches: extreme habitat degradation, commensalism, and non-limiting or super-abundant resources. These conceptual differences affect the role of NCT in unifying ecology and evolutionary biology.

scholarly journals Distance from Africa, not climate, explains within-population phenotypic diversity in humans

2008 ◽  
Vol 276 (1658) ◽  
pp. 809-814 ◽  
Author(s):  
Lia Betti ◽  
François Balloux ◽  
William Amos ◽  
Tsunehiko Hanihara ◽  
Andrea Manica
Keyword(s):  
Climatic Factors ◽  
Phenotypic Diversity ◽  
Morphological Diversity ◽  
Sub Saharan Africa ◽  
Relative Role ◽  
Morphometric Traits ◽  
Perfect Agreement ◽  
Skull Measurements ◽  
Sub Saharan

The relative importance of ancient demography and climate in determining worldwide patterns of human within-population phenotypic diversity is still open to debate. Several morphometric traits have been argued to be under selection by climatic factors, but it is unclear whether climate affects the global decline in morphological diversity with increasing geographical distance from sub-Saharan Africa. Using a large database of male and female skull measurements, we apply an explicit framework to quantify the relative role of climate and distance from Africa. We show that distance from sub-Saharan Africa is the sole determinant of human within-population phenotypic diversity, while climate plays no role. By selecting the most informative set of traits, it was possible to explain over half of the worldwide variation in phenotypic diversity. These results mirror those previously obtained for genetic markers and show that ‘bones and molecules’ are in perfect agreement for humans.

scholarly journals Morphological diversity in tenrecs (Afrosoricida, Tenrecidae): comparing tenrec skull diversity to their closest relatives

2015 ◽  
Author(s):  
Sive Finlay ◽  
Natalie Cooper
Keyword(s):  
Quantitative Analysis ◽  
Quantitative Methods ◽  
Morphological Diversity ◽  
Lateral View ◽  
Ecological Niches ◽  
Diverse Group ◽  
Geometric Morphometric ◽  
Skull Shape ◽  
Morphometric Analyses ◽  
The Family

Morphological diversity is often studied qualitatively. However, to truly understand the evolution of exceptional diversity, it is important to take a quantitative approach instead of relying on subjective, qualitative assessments. Here, we present a quantitative analysis of morphological diversity in a Family of small mammals, the tenrecs (Afrosoricida, Tenrecidae). Tenrecs are often cited as an example of an exceptionally morphologically diverse group. However, this assumption has not been tested quantitatively. We use geometric morphometric analyses of skull shape to test whether tenrecs are more morphologically diverse than their closest relatives, the golden moles (Afrosoricida, Chrysochloridae). Tenrecs occupy a wider range of ecological niches than golden moles so we predict that they will be more morphologically diverse. Contrary to our expectations, We find that tenrec skulls are only more morphologically diverse than golden moles when measured in lateral view. Furthermore, similarities among the species-rich Microgale tenrec Genus appear to mask higher morphological diversity in the rest of the Family. These results reveal new insights into the morphological diversity of tenrecs and highlight the importance of using quantitative methods to test qualitative assumptions about patterns of morphological diversity.

scholarly journals Quantitative resistance loci to southern rust mapped in a temperate maize diversity panel

2021 ◽  
Author(s):  
Guangchao Sun ◽  
Ravi V. Mural ◽  
Jonathan D. Turkus ◽  
James C. Schnable
Keyword(s):  
Disease Severity ◽  
Quantitative Resistance ◽  
Association Studies ◽  
Disease Incidence ◽  
Genome Wide Association Studies ◽  
Maize Germplasm ◽  
Photosynthetic Productivity ◽  
Maize Diversity ◽  
Puccinia Polysora ◽  
Candidate Loci

Southern rust is a severe foliar disease of maize (Zea mays) resulting from infection with the obligate biotrophic fungus Puccinia polysora. This disease reduces photosynthetic productivity, which in turn reduces yields, with the greatest yield losses (up to 50%) associated with earlier onset infections. P. polysora urediniospores overwinter only in tropical and subtropical regions but cause outbreaks when environmental conditions favor initial infection. Increased temperatures and humidity during the growing season combined with an increased frequency of moderate winters are likely to increase the frequency of severe southern rust outbreaks in the US corn belt. In summer 2020, a severe outbreak of southern rust was observed in eastern Nebraska (NE), USA. We scored a replicated maize association panel planted in Lincoln, NE for disease severity and found that disease incidence and severity showed significant variation among maize genotypes. Genome-wide association studies identified four loci associated with significant quantitative variation in disease severity. These loci were associated with candidate genes with plausible links to quantitative disease resistance. A transcriptome-wide association study identified additional genes associated with disease severity. Together, these results indicate that substantial diversity in resistance to southern rust exists among current temperate-adapted maize germplasm, including several candidate loci that may explain the observed variation in resistance to southern rust.

scholarly journals MOTIVATION OF ENTREPRENEURIAL ACTIVITY IN THE CONTEXT OF THE PROBLEM APPROACH

2020 ◽  
pp. 108-118
Author(s):  
Roman Zavadyak ◽  
◽  
Ivan Kachur ◽  
Kristian Popovych ◽  
Keyword(s):  
Business Environment ◽  
Entrepreneurial Activity ◽  
Modern Concept ◽  
Internal Motivation ◽  
Wide Range ◽  
Method Of Solution ◽  
Place Of Origin ◽  
Definition Of ◽  
Time Of Origin ◽  
Internal Potential

The aim is to study the essence of entrepreneurial activity and modern motivational concepts, which allows you to identify and systematize the main problems of motiva-ting business activity.The study showed that the motivation of entrepreneurial activity is a complex phenomenon that affects both the internal potential of the business and various counterparties and the business environment as a whole. The main elements of motivation of entrepreneurial activity are: self-motivation of a business actor (any activity will not be effective without internal motivation), staff motivation (entrepreneurship is the result of attracting various resources, including labor, which should be stimulated to achieve goals of the organization) and motivation of third parties who contact the business directly or indirectly.The constructed triangle of motivation provides opportunities in the course of practical activity of business to allocate the basic directions of diagnostics of problems of motivation of business activity.The study showed that there is a wide range of problems of business motivation, among which the determinants are: the first group of problems, covering research and activation of motives for starting your own business, starting a business; the second group of problems concerns the definition of the essence of business motivation, is to diagnose the needs on which the modern concept of motivation is based; problems of motivation of entrepreneurial activity are also in the socio-cultural environment, which can stimulate the start of business or inhibit initiative; problems of existence and emergence of contradictions in the process of business activity, which have the prospect of becoming a conflict of interest of various participants in the economic pro-cess. It is proposed to systematize the problems of motivation of entrepreneurial activity on the basis of classification according to the following features: depending on the place of origin, the time of origin, the method of solution, the complexity.

scholarly journals Virgin forests as environmental, educational and scientific object of the Ukrainian Carpathians

2019 ◽  
Vol 53 ◽  
pp. 210-219
Author(s):  
Andrii Manko ◽  
Petro Voitkiv ◽  
Yurii Nakonechnyi
Keyword(s):  
Cognitive Functions ◽  
Forest Ecosystems ◽  
Biosphere Reserve ◽  
Anthropogenic Activity ◽  
Conservation Areas ◽  
Cultural Objects ◽  
The Subject ◽  
Set Up ◽  
Definition Of ◽  
Ancient Forests

The virgin forests of the Ukrainian Carpathians are unique ecosystems in which preserved natural, protected, recreational, historical and cultural objects. That is why a comprehensive study of the forest ecosystems of the Ukrainian Carpathians is needed in order to preserve these unique treasures of our country. The Ukrainian Carpathians are characterized in ecological, educational and scientific-cognitive aspects, as a significant number of objects and monuments of nature, history, architecture and culture are concentrated here. In the region under study, there is a well-developed network of nature reserve fund, the objects of which are basic for the organization of tourist activity. The importance of virgin forests as an ecological-educational and scientific-cognitive object of the Ukrainian Carpathians is revealed. The purpose of the research was to study the forests of the Ukrainian Carpathians, as an object of ecological, educational and cognitive perception. The object of the research was the forest ecosystems within the conservation areas of the Ukrainian Carpathians. The subject of the study was the consideration of forest ecosystems as an ecological-educational and scientific-cognitive object. To achieve this goal, the following tasks were set: to give a complete definition of the term “primaeval” forests and their varieties; to identify, establish distribution areas and forest areas in the Ukrainian Carpathians; to analyze their ecological-educational and scientific-cognitive functions. It is revealed that the centres of distribution of forest ecosystems in the Ukrainian Carpathians are nature conservation areas, namely: Carpathian Biosphere Reserve, Carpathian National Park, Uzhansky, Synevyr Verkhovyna, Cheremosky, Hutsulshchyna, Vyzhnytsya, Zacharovanyi Krai. It is stated that ecological-educational and scientific-cognitive objects in the region are natural undisturbed by the anthropogenic activity of the place. The best network of ecological-educational and scientific-educational trails is set up in the Carpathian Biosphere Reserve. The most popular are the eco-routes “To Goverla Mountain from Lazeshchyna”, “Kevelsky Forests to Petros”, “Beech Forests of Velyka Ugolka”, “To Sokolino Berdo”. It is revealed that the ecological-educational and scientific-cognitive potential of the forests of the Ukrainian Carpathians is special. The primaeval forests are widespread in the Ukrainian Carpathians, and their area is about 50 thousand hectares, and much of it requires identification. Forests have a special status in Ukraine and are strictly protected in nature reserves and perform ecological-educational and scientific-cognitive functions, since within them preserved natural, intact, virgin objects and also represent the cultural heritage of the region. Key words: Ukrainian Carpathians, virgin forests, quasi-virgin forests, ancient forests, ecological-educational and scientific-cognitive objects.

scholarly journals Creating Porcine Biomedical Models Through Recombineering

2004 ◽  
Vol 5 (3) ◽  
pp. 262-267 ◽  
Author(s):  
Margarita M. Rogatcheva ◽  
Laurie A. Rund ◽  
Kelly S. Swanson ◽  
Brandy M. Marron ◽  
Jonathan E. Beever ◽  
...  
Keyword(s):  
Genetic Information ◽  
Positional Cloning ◽  
Reverse Genetics ◽  
Genetic Model ◽  
Phenotypic Diversity ◽  
Model Organism ◽  
Artificial Chromosome ◽  
Forward Genetics ◽  
Working Definition ◽  
Definition Of

Recent advances in genomics provide genetic information from humans and other mammals (mouse, rat, dog and primates) traditionally used as models as well as new candidates (pigs and cattle). In addition, linked enabling technologies, such as transgenesis and animal cloning, provide innovative ways to design and perform experiments to dissect complex biological systems. Exploitation of genomic information overcomes the traditional need to choose naturally occurring models. Thus, investigators can utilize emerging genomic knowledge and tools to create relevant animal models. This approach is referred to as reverse genetics. In contrast to ‘forward genetics’, in which gene(s) responsible for a particular phenotype are identified by positional cloning (phenotype to genotype), the ‘reverse genetics’ approach determines the function of a gene and predicts the phenotype of a cell, tissue, or organism (genotype to phenotype). The convergence of classical and reverse genetics, along with genomics, provides a working definition of a ‘genetic model’ organism (3). The recent construction of phenotypic maps defining quantitative trait loci (QTL) in various domesticated species provides insights into how allelic variations contribute to phenotypic diversity. Targeted chromosomal regions are characterized by the construction of bacterial artificial chromosome (BAC) contigs to isolate and characterize genes contributing towards phenotypic variation. Recombineering provides a powerful methodology to harvest genetic information responsible for phenotype. Linking recombineering with gene-targeted homologous recombination, coupled with nuclear transfer (NT) technology can provide ‘clones’ of genetically modified animals.

scholarly journals Deciphering African late middle Pleistocene hominin diversity and the origin of our species

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Aurélien Mounier ◽  
Marta Mirazón Lahr
Keyword(s):  
Homo Sapiens ◽  
Morphological Diversity ◽  
Middle Pleistocene ◽  
Last Common Ancestor ◽  
North African ◽  
East African ◽  
Complex Process ◽  
Source Populations ◽  
Definition Of ◽  
Late Middle Pleistocene

Abstract The origin of Homo sapiens remains a matter of debate. The extent and geographic patterning of morphological diversity among Late Middle Pleistocene (LMP) African hominins is largely unknown, thus precluding the definition of boundaries of variability in early H. sapiens and the interpretation of individual fossils. Here we use a phylogenetic modelling method to predict possible morphologies of a last common ancestor of all modern humans, which we compare to LMP African fossils (KNM-ES 11693, Florisbad, Irhoud 1, Omo II, and LH18). Our results support a complex process for the evolution of H. sapiens, with the recognition of different, geographically localised, populations and lineages in Africa – not all of which contributed to our species’ origin. Based on the available fossils, H. sapiens appears to have originated from the coalescence of South and, possibly, East-African source populations, while North-African fossils may represent a population which introgressed into Neandertals during the LMP.

scholarly journals Social Networks and Transnational Social Fields: A Review of Quantitative and Mixed-Methods Approaches

2018 ◽  
Vol 54 (1) ◽  
pp. 177-204 ◽  
Author(s):  
Miranda Jessica Lubbers ◽  
Ashton M. Verdery ◽  
José Luis Molina
Keyword(s):  
Social Networks ◽  
Social Network ◽  
Mixed Methods ◽  
Social Fields ◽  
Transnational Social Fields ◽  
Small Set ◽  
Individual Household ◽  
Place Of Origin ◽  
Definition Of ◽  
Transnational Social Networks

Scholars of transnationalism have argued that migrants create transnational social fields or spaces that connect their place of origin to destination areas. Despite the centrality that social networks have in the definition of these concepts, quantitative and mixed-methods social network research is rare in research on transnationalism. This situation, however, has changed over the last decade, and the transnational social networks of migrants have been studied with multiple methodologies. So far, this literature has not been systematically evaluated. With the aim of taking stock of this research, we classify the literature into four types of approaches (individual, household, dyad/small set, and community) and review their distinct contributions regarding the functioning of immigrants’ transnational networks, as well as the relative strengths and limitations of each approach. On the basis of our analysis, we discuss pathways for future investigation.

scholarly journals Genotypic and Phenotypic Diversity among Induced, stx2-Carrying Bacteriophages from Environmental Escherichia coli Strains

2008 ◽  
Vol 75 (2) ◽  
pp. 329-336 ◽  
Author(s):  
Cristina García-Aljaro ◽  
Maite Muniesa ◽  
Juan Jofre ◽  
Anicet R. Blanch
Keyword(s):  
Escherichia Coli ◽  
Shiga Toxin ◽  
Phenotypic Diversity ◽  
Morphological Diversity ◽  
Lytic Cycle ◽  
Animal Origin ◽  
Bacterial Populations ◽  
Shiga Toxin 2 ◽  
Different Strains ◽  
High Level

ABSTRACT Shiga toxin 2 (stx 2) gene-carrying bacteriophages have been shown to convert Escherichia coli strains to Shiga toxin-producing Escherichia coli (STEC). In this study, 79 E. coli strains belonging to 35 serotypes isolated from wastewaters of both human and animal origin were examined for the presence of stx2 -carrying bacteriophages in their genomes. The lytic cycle of the bacteriophages was induced by mitomycin, and the bacteriophage fraction was isolated and used for morphological and genetic characterization. The induced bacteriophages showed morphological diversity, as well as restriction fragment length polymorphism variation, in the different strains belonging to different serotypes. The ability to infect new hosts was highly variable, although most of the induced phages infected Shigella sonnei host strain 866. In summary, in spite of carrying either the same or different stx 2 variants and in spite of the fact that they were isolated from strains belonging to the same or different serotypes, the induced bacteriophages were highly variable. The high level of diversity and the great infectious capacity of these phages could enhance the spread of the stx 2 gene and variants of this gene among different bacterial populations in environments to which humans may be exposed.

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