35 research outputs found
Το λογισμικό SpatialAnalyzer & εφαρμογές του σε προβλήματα βιομηχανικής γεωδαισίας
This paper reports a first study exploring genomic prediction for adaptation of sorghum [Sorghum bicolor (L.) Moench] to drought-stress (D-ET) and nonstress (W-ET) environment types. The objective was to evaluate the impact of both modeling genotype × environment interaction (G×E) and accounting for heterogeneous variances of marker effects on genomic prediction of parental breeding values for grain yield within and across environment types (ETs). For this aim, different genetic covariance structures and different weights for individual markers were investigated in best linear unbiased prediction (BLUP)-based prediction models. The BLUP models used a kinship matrix combining pedigree and genomic information, termed K-BLUP. The dataset comprised testcross yield performances under D-ET and W-ET as well as pedigree and genomic data. In general, modeling G×E increased predictive ability and reduced empirical bias of genomic predictions for broad adaptation across both ETs vs. models that ignored G×E by fitting a main genetic effect only. Genomic predictions for specific adaptation to D-ET or W-ET were also improved by K-BLUP models that explicitly accommodated G×E and used data from both ETs relative to prediction models that used data from the targeted ET exclusively or models that used all the data but assumed no G×E. Allowing for heterogeneous marker variances through weighted K-BLUP produced clear increments (43–72%) in predictive ability of genomic prediction for grain yield in all adaptation scenarios. We conclude that G×E as well as locus-specific genetic variances should be accommodated in genomic prediction models to improve adaptability of sorghum to variable environmental conditions
Identity and integration of Russian speakers in the Baltic states: a framework for analysis
Following a review of current scholarship on identity and integration patterns of Russian speakers in the Baltic states, this article proposes an analytical framework to help understand current trends. Rogers Brubaker's widely employed triadic nexus is expanded to demonstrate why a form of Russian-speaking identity has been emerging, but has failed to become fully consolidated, and why significant integration has occurred structurally but not identificationally. By enumerating the subfields of political, economic, and cultural ‘stances’ and ‘representations’ the model helps to understand the complicated integration processes of minority groups that possess complex relationships with ‘external homelands’, ‘nationalizing states’ and ‘international organizations’. Ultimately, it is argued that socio-economic factors largely reduce the capacity for a consolidated identity; political factors have a moderate tendency to reduce this capacity, whereas cultural factors generally increase the potential for a consolidated group identity
Exome sequences and multi-environment field trials elucidate the genetic basis of adaptation in barley
Broadening the genetic base of crops is crucial for developing varieties to respond to global agricultural challenges such as climate change. Here, we analysed a diverse panel of 371 domesticated lines of the model crop of barley to explore the genetics of crop adaptation. We first collected exome sequence data and phenotypes of key life history traits from contrasting multi-environment common garden trials. Then we applied refined statistical methods, including based on exomic haplotype states, for genotype-by-environment (G
7E) modelling. Sub-populations defined from exomic profiles were coincident with barley's biology, geography and history, and explained a high proportion of trial phenotypic variance. Clear G
7E interactions indicated adaptation profiles that varied for landraces and cultivars. Exploration of circadian clock-related genes, associated with the environmentally-adaptive days to heading trait (crucial for the crop's spread from the Fertile Crescent), illustrated complexities in G
7E effect directions, and the importance of latitudinally-based genic context in the expression of large effect alleles. Our analysis supports a gene-level scientific understanding of crop adaption and leads to practical opportunities for crop improvement, allowing the prioritisation of genomic regions and particular sets of lines for breeding efforts seeking to cope with climate change and other stresses
Tracing the ancestry of modern bread wheats
For more than 10,000 years, the selection of plant and animal traits that are better tailored for human use has shaped the development of civilizations. During this period, bread wheat (Triticum aestivum) emerged as one of the world’s most important crops. We use exome sequencing of a worldwide panel of almost 500 genotypes selected from across the geographical range of the wheat species complex to explore how 10,000 years of hybridization, selection, adaptation and plant breeding has shaped the genetic makeup of modern bread wheats. We observe considerable genetic variation at the genic, chromosomal and subgenomic levels, and use this information to decipher the likely origins of modern day wheats, the consequences of range expansion and the allelic variants selected since its domestication. Our data support a reconciled model of wheat evolution and provide novel avenues for future breeding improvement.</p
Social Networks and Labor Market Inequality between Ethnicities and Races
This paper analyzes the relationship between unexplained racial/ethnic wage differentials on the one hand and social network segregation, as measured by inbreeding homophily, on the other hand. Our analysis is based on both U.S. and Estonian surveys, supplemented with Estonian telephone communication data. In case of Estonia we consider the regional variation in economic performance of the Russian minority, and in the U.S. case we consider the regional variation in black-white differentials. Our analysis finds a strong relationship between the size of the differential and network segregation: regions with more segregated social networks exhibit larger unexplained wage gaps