22 research outputs found
Whole-Genome Analysis of Diversity and SNP-Major Gene Association in Peach Germplasm
Peach was domesticated in China more than four millennia ago and from there it spread world-wide. Since the middle of the last century, peach breeding programs have been very dynamic generating hundreds of new commercial varieties, however, in most cases such varieties derive from a limited collection of parental lines (founders). This is one reason for the observed low levels of variability of the commercial gene pool, implying that knowledge of the extent and distribution of genetic variability in peach is critical to allow the choice of adequate parents to confer enhanced productivity, adaptation and quality to improved varieties. With this aim we genotyped 1,580 peach accessions (including a few closely related Prunus species) maintained and phenotyped in five germplasm collections (four European and one Chinese) with the International Peach SNP Consortium 9K SNP peach array. The study of population structure revealed the subdivision of the panel in three main populations, one mainly made up of Occidental varieties from breeding programs (POP1OCB), one of Occidental landraces (POP2OCT) and the third of Oriental accessions (POP3OR). Analysis of linkage disequilibrium (LD) identified differential patterns of genome-wide LD blocks in each of the populations. Phenotypic data for seven monogenic traits were integrated in a genome-wide association study (GWAS). The significantly associated SNPs were always in the regions predicted by linkage analysis, forming haplotypes of markers. These diagnostic haplotypes could be used for marker-assisted selection (MAS) in modern breeding programs
Evolution and new frontiers of histology in bio\u2010medical research
Histology refers to the study of the morphology of cells within their natural tissue environment. As a bio\u2010medical discipline, it dates back to the development of first microscopes which allowed to override the physical visual limitation of the human eye. Since the first observations, it was understood that cell shape predicts function and, therefore, shape alterations can identify and explain dysfunction and diseases. The advancements in morphological investigation techniques have allowed to extend our understanding of the shape\u2013function relationships close to the molecular level of organization of tissues, as well as to derive reliable data not only from fixed, and hence static, biological samples but also living cells and tissues and even for extended time periods. These modern approaches, which encompass quantitative microscopy, precision microscopy, and dynamic microscopy, represent the new frontier of morphology. This article summarizes how the microscopy techniques have evolved to properly face the challenges of biomedical sciences, thus transforming histology from a merely qualitative discipline, which played an ancillary role to traditional \u201cmajor\u201d sciences such as anatomy, to a modern experimental science capable of driving knowledge progress in biology and medicine
Bacterial wilt, caused by <i>Ralstonia solanacearum</i>, on tomato in Italy
Symptoms of wilting, resembling those incited by
Ralstonia solanacearum, were observed in February and April 2007 on tomato (Lycopersicon esculentum) cvs Arawak, Ikram and Cuore di bue, growing in five greenhouses
in Southern Sardinia (Italy). At first affected plants showed collapse of the
growing apex. Stunted lateral shoots emerged but then wilted and died
while adventitious roots appeared on the stems. Cross sections of stems
showed brown discoloration of the vascular tissue and oozed a dirty white
exudate. In April, when environmental conditions were warmer, wilting of
the whole plant occurred rapidly. The percentage of wilted plants ranged
from 10 to 70%
Investigation of ÎČ-hydroxybutyrate in early lactation of Simmental cows: Genetic parameters and genomic predictions
Genomic information allows for a more accurate calculation of relationships among animals than the pedigree information, leading to an increase in accuracy of breeding values. Here, we used pedigreeâbased and singleâstep genomic approaches to estimate variance components and breeding values for ÎČâhydroxybutyrate milk content (BHB). Additionally, we performed a genomeâwide association study (GWAS) to depict its genetic architecture. BHB concentrations within the first 90 days of lactation, estimated from milk medium infrared spectra, were available for 30,461 cows (70,984 records). Genotypes at 42,152 loci were available for 9,123 animals. Low heritabilities were found for BHB using pedigreeâbased (0.09 ± 0.01) and genomic (0.10 ± 0.01) approaches. Genetic correlation between BHB and milk traits ranged from â0.27 ± 0.06 (BHB and protein percentage) to 0.13 ± 0.07 (BHB and fatâtoâprotein ratio) using pedigree and from â0.26 ± 0.05 (BHB and protein percentage) to 0.13 ± 0.06 (BHB and fatâtoâprotein ratio) using genomics. Breeding values were validated for 344 genotyped cows using linear regression method. The genomic EBV (GEBV) had greater accuracy (0.51 vs. 0.45) and regression coefficient (0.98 vs. 0.95) compared to EBV. The correlation between two subsequent evaluations, without and with phenotypes for validation cows, was 0.85 for GEBV and 0.82 for EBV. Predictive ability (correlation between (G)EBV and adjusted phenotypes) was greater when genomic information was used (0.38) than in the pedigreeâbased approach (0.31). Validation statistics in the pairwise twoâtrait models (milk yield, fat and protein percentage, urea, fat/protein ratio, lactose and logarithmic transformation of somatic cells count) were very similar to the ones highlighted for the singleâtrait model. The GWAS allowed discovering four significant markers located on BTA20 (57.5â58.2 Mb), where the ANKH gene is mapped. This gene has been associated with lactose, alphaâlactalbumin and BHB. Results of this study confirmed the usefulness of genomic information to provide more accurate variance components and breeding values, and important insights about the genomic determination of BHB milk content