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Evolutionary processes and its environmental correlates in the cranial morphology of western chipmunks (Tamias).
The importance of the environment in shaping phenotypic evolution lies at the core of evolutionary biology. Chipmunks of the genus Tamias (subgenus Neotamias) are part of a very recent radiation, occupying a wide range of environments with marked niche partitioning among species. One open question is if and how those differences in environments affected phenotypic evolution in this lineage. Herein we examine the relative importance of genetic drift versus natural selection in the origin of cranial diversity exhibited by clade members. We also explore the degree to which variation in potential selective agents (environmental variables) are correlated with the patterns of morphological variation presented. We found that genetic drift cannot explain morphological diversification in the group, thus supporting the potential role of natural selection as the predominant evolutionary force during Neotamias cranial diversification, although the strength of selection varied greatly among species. This morphological diversification, in turn, was correlated with environmental conditions, suggesting a possible causal relationship. These results underscore that extant Neotamias represent a radiation in which aspects of the environment might have acted as the selective force driving species' divergence
Influence of bunch exposure on anthocyanins extractability from grapes skins (Vitis vinifera L.)
In relation to bunch exposure to solar irradiance (sun exposed vs. leaf shaded conditions), anthocyanin ripening and extractability were studied in two grape cultivars ('Croatina' and 'Pinot Noir') coming from three different vineyards in Northern Italy. Analysis of anthocyanin content were carried out by HPLC and spectrophotometry, and a simulated maceration process was developed. Pigments extraction occurred mainly in the first few hours of the maceration process. Anthocyanins with disubstituted B-ring showed a faster extractability than the trisubsituted ones. Bunch exposure to sunlight seemed to be important for pigment extractability timing in winemaking, showing a delay in pigments release. This delay was only partially explained by the different pigments profile, with higher percentage of disubstituted compounds in shaded berries, because all the molecules indicated a similar extraction trend during maceration.
Genetic relationships among grapevine cultivars grown in Oltrepò Pavese (Italy)
In order to evaluate the genetic distance among 47 grapevine accessions, including major and minor local cultivars grown in Oltrepò pavese (Pavia, Italy), DNA has been analysed with the AFLP approach (VOS et al. 1995). The electrophoretic analysis of the products amplified by 3 primer combinations showed high polymorphism.Furthermore, considering that DNA markers for haploid, uniparentally inherited genomes, such as the chloroplast DNA, are important indicators of pedigree, CpSSR analysis was also performed and this identified cases of maternal common origin among the analysed cultivars. The results show that these molecular tools allow univocal genotype identification and that the analysed germplasm has a wide genetic dissimilarity. Results are coherent with the postulation of a polycentric origin for the Oltrepò pavese cultivars and of a multiple varietal flow from different viticultural regions. The molecular information gathered in this research is essential for the establishment of an appropriate presentation programme of autochthonous varieties
Genetic analysis of rennet coagulation time, curd-firming rate, and curd firmness assessed over an extended testing period using mechanical and near-infrared instruments
Abstract The aims of this study were (1) to analyze rennet coagulation time (RCT), curd-firming rate, and curd firmness obtained by extending the standard 30-min testing time to 45min; (2) to estimate heritabilities of the aforementioned traits determined by mechanical (Formagraph; Foss Electric, Hillerod, Denmark) and near-infrared optical (Optigraph; Ysebaert, Frepillon, France) instruments, and to assess the statistical relevance of their genetic background by using the Bayes factor procedure, the deviance information criterion, and the mean squared error; (3) to estimate phenotypic and genetic relationships between instruments within trait and between traits within instrument; and (4) to obtain correlations for sire rankings based on the used instruments. Individual milk samples were collected from 913 Brown Swiss cows reared in 63 herds located in Trento Province (Italy). Milk coagulation properties (MCP) were measured using 2 different instruments: Formagraph and Optigraph. Both instruments were housed in the same laboratory and operated by the same technician. Each sample was analyzed simultaneously on each instrument. All experimental conditions (milk temperature and the concentration and type of rennet) were identical. For the analysis, univariate and bivariate animal models were implemented using Bayesian methods. Univariate analyses were conducted to test the hypothesis that the traits showed additive genetic determination. Deviance information criterion, Bayes factor, and mean squared error were used as model choice criteria. The main results were that (1) RCT could be measured on all samples by extending the observation time to 45min, and its genetic parameters ( h 2 =0.23) and breeding values could be estimated while avoiding the bias of noncoagulating samples; (2) curd-firming rate could be measured on almost all milk samples, and its genetic parameters could be estimated for the first time on a field data set ( h 2 =0.21); (3) for the first time, genetic parameters of curd firmness 45min after rennet addition ( h 2 =0.12) were estimated, and they were compared with curd firmness 30min after rennet addition ( h 2 =0.17); and (4) MCP estimated using the Optigraph appeared to be genetically different from those determined by Formagraph, with the partial exception of RCT (genetic correlation=0.97). Breeding strategies for the improvement of MCP must be planned with caution. Currently, the high throughput, ease of use, and reduced costs of analysis make predictions obtained from mid-infrared spectroscopy (MIRS) on untreated milk samples a promising alternative to produce relevant data at the population level. The use of mechanical lactodynamographs to establish reference data for MIRS calibrations have been already studied, whereas the use of near-infrared optical lactodynamographs as a reference method for MIRS calibrations needs to be investigated
Molecular approach to assess the origin of cv. Marzemino
DNA marker analysis was used to determine the varietal identity of Marzemino accessions in public collections and private Italian vineyards; relationships among this varietal group and Vertzami, a traditional Greek cultivar, were also investigated through SSR and AFLP approaches. Molecular results strongly support the relationship among Vertzami cultivars growing in Greece, Marzemino and several Italian accessions selected on the basis of etymological similarity. SSR data exclude a direct descent of Marzemino, or other related Italian varieties, from Vertzami; on the other hand the level of similarity among Vertzami, Marzemino and some related varieties indicates a possible common ancestor. None of the accessions is considered as common ancestor but on the basis of genomic variability in the Marzemino group and of the relationships with the other Italian cultivars a probable Italian ancestor is supposed.
Systems Biology of Cold Adaptation in the Polyextremophilic Red Alga Galdieria sulphuraria
Rapid fluctuation of environmental conditions can impose severe stress upon living organisms. Surviving such episodes of stress requires a rapid acclimation response, e.g., by transcriptional and post-transcriptional mechanisms. Persistent change of the environmental context, however, requires longer-term adaptation at the genetic level. Fast-growing unicellular aquatic eukaryotes enable analysis of adaptive responses at the genetic level in a laboratory setting. In this study, we applied continuous cold stress (28°C) to the thermoacidophile red alga G. sulphuraria, which is 14°C below its optimal growth temperature of 42°C. Cold stress was applied for more than 100 generations to identify components that are critical for conferring thermal adaptation. After cold exposure for more than 100 generations, the cold-adapted samples grew ∼30% faster than the starting population. Whole-genome sequencing revealed 757 variants located on 429 genes (6.1% of the transcriptome) encoding molecular functions involved in cell cycle regulation, gene regulation, signaling, morphogenesis, microtubule nucleation, and transmembrane transport. CpG islands located in the intergenic region accumulated a significant number of variants, which is likely a sign of epigenetic remodeling. We present 20 candidate genes and three putative cis-regulatory elements with various functions most affected by temperature. Our work shows that natural selection toward temperature tolerance is a complex systems biology problem that involves gradual reprogramming of an intricate gene network and deeply nested regulators
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