A collection of 1005 grapevine accessions was genotyped at 34 microsatellite loci (SSR) with the aim of analysing genetic diversity and exploring parentages. The comparison of molecular profiles revealed 200 groups of synonymy. The removal of perfect synonyms reduced the database to 745 unique genotypes, on which population genetic parameters were calculated. The analysis of kinship uncovered 74 complete pedigrees, with both parents identified. Many of these parentages were not previously known and are of considerable historical interest, e.g. Chenin blanc (Sauvignon × Traminer rot), Covè (Harslevelu selfed), Incrocio Manzoni 2-14 and 2-15 (Cabernet franc × Prosecco), Lagrein (Schiava gentile × Teroldego), Malvasia nera of Bolzano (Perera × Schiava gentile), Manzoni moscato (Raboso veronese × Moscato d'Amburgo), Moscato violetto (Moscato bianco × Duraguzza), Muscat of Alexandria (Muscat blanc à petit grain × Axina de tres bias) and others. Statistical robustness of unexpected pedigrees was reinforced with the analysis of an additional 7-30 SSRs. Grouping the accessions by profile resulted in a weak correlation with their geographical origin and/or current area of cultivation, revealing a large admixture of local varieties with those most widely cultivated, as a result of ancient commerce and population flow. The SSRs with tri- to penta-nucleotide repeats adopted for the present study showed a great capacity for discriminating amongst accessions, with probabilities of identity by chance as low as 1.45 × 10(-27) and 9.35 × 10(-12) for unrelated and full sib individuals, respectively. A database of allele frequencies and SSR profiles of 32 reference cultivars are provided.
Salix albaÀSalix fragilis complex includes closely related dioecious polyploid species, which are obligate outcrossers. Natural populations of these willows and their hybrids are represented by a mixture of highly heterozygous genotypes sharing a common gene pool. Since nothing is known about their genomic constitution, tetraploidy (2n ¼ 4x ¼ 76) in willow species makes basic and applied genetic studies difficult. We have used a two-way pseudotestcross strategy and singledose markers (SDMs) to construct the first linkage maps for both pistillate and staminate willows. A total of 242 amplified fragment length polymorphisms (AFLPs) and 50 selective amplifications of microsatellite polymorphic loci (SAMPL) markers, which showed 1:1 segregation in the F 1 mapping populations, were used in linkage analysis. In S. alba, 73 maternal and 48 paternal SDMs were mapped to 19 and 16 linkage groups covering 708 and 339 cM, respectively. In S. fragilis, 13 maternal and 33 paternal SDMs were mapped in six and 14 linkage groups covering 98 and 321 cM, respectively. For most cosegregation groups, a comparable number of markers linked in coupling and repulsion was identified. This finding suggests that most of chromosomes pair preferentially as occurs in allotetraploid species exhibiting disomic inheritance. The detection of 10 pairs of marker alleles from single parents showing codominant inheritance strengthens this hypothesis. The fact that, of the 1122 marker loci identified in the two male and female parents, the vast majority (77.5%) were polymorphic and as few as 22.5% were shared between parental species highlight that S. alba and S. fragilis genotypes are differentiated. The highly difference between S. alba-and S. fragilis-specific markers found in both parental combinations (on average, 65.3 vs 34.7%, respectively) supports the (phylogenetic) hypothesis that S. fragilis is derived from S. alba-like progenitors.
Clonal selection is the most worldwide spreading method to improve the performance of wine grapevine (Vitis vinifera) cultivars. In the special case of autochthonous varieties with only local interest, such as Manto Negro, Callet and Moll in Majorca (Spain), good knowledge of their genotypic resources is helpful to assess the development of viticultural and enological potentialities. In this study, 94 vines (including Manto Negro, Callet, Moll and wrongly identified samples) were analysed by means of genetic markers. Several varietal identification mistakes related to the clonal selection in Majorca were detected by the amplification of 33 simple sequence repeats (SSRs) or microsatellite loci, mainly because of the close genetic relationships between Manto Negro, Callet, Moll and other varieties. A very low degree of intravarietal genetic diversity, possibly related to high incidence of virus infections, was shown in all three varieties. However, analysis by amplified fragment length polymorphism (AFLP), selective amplification of microsatellite loci (SAMPL) and microsatellite-amplified fragment length polymorphism (M-AFLP) was suitable for clone genetic discrimination. More than 900 scorable bands were obtained by nine primer combinations. The most efficient system to detect intravarietal genetic differences was M-AFLP, which generated the highest number of polymorphic bands. The use of these markers allowed clustering vines in homogeneous groups, providing essential information about sanitation strategies in order to obtain certified propagation material.
This study uses PCR-derived marker systems to investigate the extent and distribution of genetic variability of 53 Garnacha accessions coming from Italy, France and
To determine the effect of a short course of methylxanthines on renal function and on urinary calcium excretion, 20 premature neonates affected by apnea or moderate respiratory distress syndrome were randomly assigned to either a theophylline treatment or to a caffeine treatment group. The protocol included a 24-hour pretreatment study period (I) and a subsequent 24-hour period (II) following 5 days of theophylline (loading dose 5 mg/kg i.v., maintenance dose 2.5 mg/kg/l2 h) or caffeine (loading dose 10 mg/kg i.v., maintenance dose 2.5 mg/kg/l2 h) administration. Pre- and postxanthine treatment serum sodium, potassium, calcium and phosphorus remained stable, while serum creatinine decreased significantly (p < 0.05). Furthermore, from period I to period II, sodium urine excretion, fractional Na excretion and creatinine clearance remained statistically comparable in both study groups, along with a significant increase (p < 0.05) in calciuria, urinary Ca/creatinine and urinary Ca/Na. Predose caffeine and theophylline serum levels, assessed on the 5th day of treatment, were 12.8 ± 1.8 and 7.9 ± 1.7 μg/ml, respectively. Compared to control healthy untreated prematures, the studied premature infants showed a statistically significant increase in urine calcium excretion (10- to 15-fold), which was more evident in the theophylline group. Our data suggest further investigation to determine the long-term renal effects of methylxanthines in premature neonates, to improve assessment of the risk of nephrocalcinosis and osteopenia, in particular in association with various diuretic therapies.
Mutants showing features of apomixis have been documented in alfalfa (Medicago sativa L.), a natural outcrossing sexual species. A differential display of mRNAs that combines cDNA-AFLP markers and bulked segregant analysis was carried out with the aim of selecting expressed sequence tags (ESTs) and cloning candidate genes for apomeiosis in mutants of alfalfa characterized by 2n egg formation at high frequencies. The approach enabled us to select either mutant- or wild type-specific transcript derived-fragments and to detect transcriptional changes potentially related to 2n eggs. Sequence alignments of a subset of 40 polymorphic clones showed significant homologies to genes of known function. An EST with identity to a β-tubulin gene, highly expressed in the wild type and poorly expressed in the apomeiotic mutants, and an EST with identity to a Mob1-like gene, qualitatively polymorphic between pre- and post-meiotic stages, were selected as candidate genes for apomeiosis because of their putative roles in the cell cycle. A number of clone-specific primers were designed for performing both 5' and 3' rapid amplification of cDNA ends to obtain the full-length clones. Southern blot hybridization revealed that both clones belong to a multi-gene family with a minimum of three genomic DNA members each. Northern blot hybridization of total RNA samples and in situ hybridization of whole buds enabled the definition of their temporal and spatial expression patterns in reproductive organs. Experimental achievements towards the elucidation of apomeiotic megasporogenesis in alfalfa are presented and discussed.
Abstract:The Salix alba L. (white willow)-Salix fragilis L. (crack willow) complex includes closely related polyploid species, mainly tetraploid (2n = 4x = 76), which are dioecious and hence obligate allogamous. Because little is known about the genome constitution and chromosome behavior of these pure willow trees, genetic analysis of their naturally occurring interspecific polyploid hybrids is still very difficult. A two-way pseudo-testcross strategy was exploited using single-dose AFLP markers in order to assess the main inheritance patterns of tetraploid biotypes (disomy vs. tetrasomy) in segregating populations stemmed from S. alba × S. fragilis crosses and reciprocals. In addition, a genomic in situ hybridization (GISH) technology was implemented in willow to shed some light on the genome structure of S. alba and S. fragilis species, and their hybrids (allopolyploidy vs. autopolyploidy). The frequency of S. alba-specific molecular markers was almost double compared to that of S. fragilis-specific ones, suggesting the phylogenetic hypothesis of S. fragilis as derivative species from S. alba-like progenitors. Cytogenetic observations at pro-metaphase revealed about half of the chromosome complements being OPEN ACCESS Diversity 2014, 6 634 less contracted than the remaining ones, supporting an allopolyploid origin of both S. alba and S. fragilis. Both genetic segregation and genomic hybridization data are consistent with an allotetraploid nature of the Salix species. In particular, the vast majority of the AFLP markers were inherited according to disomic patterns in S. alba × S. fragilis populations and reciprocals. Moreover, in all S. alba against S. fragilis hybridizations and reciprocals, GISH signals were observed only on the contracted chromosomes whereas the non-contracted chromosomes were never hybridized. In conclusion, half of the chromosomes of the pure species S. alba and S. fragilis are closely related and they could share a common diploid ancestor, while the rest of chromosomes are morphologically differentiated in either S. alba or S. fragilis and they should derive from distinct diploid ancestors.
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