Molecular genetics

Molekulargenetik
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Designation of a branch of molecular biology to study the structure of the genome (all the genes in an organism) and the function and the interaction of genes (in the chromosomes of each cell nucleus to the DNA localized genetic factors). Genetic engineering or is the application of genetic methods for practice and usually means the artificial genetic manipulation with the aim of Neueinbringung of desired, not yet existing properties such as Resistance against Mushrooms into an existing organism is technically feasible by implanting single remanufactured foreign genes into the genome of organisms belonging to an existing variety or breed.

Since the invention of PCR (Polymerase chain reaction) to amplify the smallest DNA in the 1990s, varieties can now also using molecular genetic characterization methods to define genotypically characterize varieties clearly, and recognize. This was the Genotype in the Ampelography introduced that as a complement to traditional, visually the Phenotype may help to clarify many based ampelography still open questions. Each self-contained, sprouted from a seed variety is represented by a unique genotype, which is characterized by a unique recombination of maternal and paternal genes during fertilization and in the nucleus of every plant cell is present. Each resulting from sexual reproduction Grape (Like any other individual from sexual reproduction that emerged as well) has an individual genetic pattern that distinguishes it from all other varieties.

For genotypic comparisons of varieties, one uses the genetic fingerprint that can be created with the so-called microsatellite analysis. Microsatellites are defined by molecular markers, re-find areas within the long DNA Having a different number of repeating base sequences. This double set of chromosomes when given the vine (2n = 38) twice repeated sequences, both between two homologous chromosomes as well as grape variety to be of different lengths. You can copy these areas as individual fragments, and multiply, so that one gets by the length of the genome fragments specific characteristic.

Many such pairs always present fragments from several loci yield a specific, varietal and this species distinctive fragment pattern that can be matched against the fragment patterns of other varieties. This fragment pattern is a sort of genetic fingerprint (fingerprint). The probability that two varieties have the same pattern is statistically about 1:6 million, with only about 14,000 existing varieties and breeding lines a vanishingly small probability. Within the European vine-growing institutions there is an agreement that the genotypic characterization of varieties therefore already sufficient to determine the genotype at six defined loci (microsatellites) to define the profile of a species unique.

Before the method of microsatellite analysis was invented, variety and varietal comparisons were accrued only on the comparative Morphology (Outer shape) of the Vine possible. They described the characteristics of the variety of the plant and tried to filter out features that made it possible to identify the species and to distinguish each other. This morphological feature catalogs describe the Phenotype the vine. Both approaches have advantages and disadvantages of complement, but wonderful. Genetic analyzes in the laboratory require only a small amount of genetic material as a starting material, the tests are not dependent on external conditions such as season, plant age, health status, virus status or growth conditions at the site, the phenotype (the appearance) can distort beyond recognition.

However, laboratory tests cost money and time and can not blindly be performed on thousands of vines in the field, as is quickly and without additional cost to the trained eye of ampelographers possible. Also, varieties, or clones of the mutated as somatic chimeras Vegetative propagation arose, still better distinguish phenotypically. Because the color of the mutants Pinot Noir , Namely Pinot Gris and Pinot Blanc are still not distinguishable with the genetic fingerprint (and virtually identical), as well as somatic chimeras Meunier (Pinot Meunier) or Lladoner Pelut are easier and faster by the visually strong leaf pubescence of the origin of varieties and Pinot Noir Grenache Noir (Garnacha Tinta) differentiate as by complex genetic analyzes.

To characterize the current cultivars using microsatellite analysis experience, ranging from the six internationally designated marker. The "Six-Marker theory," but says only that it is just enough to study a variety of at least six loci in order to get a unique, individual trait combination that is unmatched by any other grape variety more. For other questions, such as the elucidation of relationships or even the definition of Clone and somatic Chimera use within a variety must be clearly more markers. There is a rare exception that two outwardly different varieties Phenotype (Varieties) the same genotypic profile at six markers have.

Such a thing can occur when a variety of Mutation branched off in specific cell layers (for example in the epidermis) has a somatic chimera having at a few loci now three instead of two distinct fragments. Even with species that are formed by self-or backcross (mother and child), can use less marker genotypes in the still very similar. In both cases you have more markers (more than six) to take in order to detect the genotypic differences. Conversely, genetically distinct genotypes easily result in phenotypes that look confusingly similar. Especially in places with the same parents, siblings, this can sometimes be the failure of the purely visual identification test lead in the field.

As with the paternity test can be reconstructed with the help of DNA fingerprinting for the first time and pedigrees, to determine relationships or cross-breeding of Hybrids . recognize Provided, however, is a comprehensive genetic analysis of at least 15 to 50 loci. Since each child has one chromosome from the father and one inherited from the mother, every vine at a specific locus is also a characteristic of each type with the father and the other places have in common with the mother. This rule is strictly valid, that is, a failure to meet the origin criterion usually means the end of the descent hypothesis.

The more loci are involved in the investigation, the more reliable the lineage hypothesis, given the types of parent strain has been found only once. However, a 100% proof erbringbar not because the hypotheses are only a few select, but can never be tested positive at all loci. In addition, the types of mutations involved have occurred in the centuries between birth and genotypic analysis, so that the hypothesis to be proven pedigree at about 1 to 2 of 50 loci may be true.

Using paternity analysis, some important Central European Leitsorten as Heunisch , Pinot Noir or Traminer are identified. High vine age and the prevalence were favorable for the spontaneous crossing of these varieties. The average age everywhere cultivated Heunisch has been crossed only in 80 varieties. Often used in the formulation of sources "is not directly related." This is usually meant that between the varieties considered not a "mother-father-child relationship" is. Direct relationships between varieties (ie "mother-father-child") are clearly linked to reconstruct the genetic fingerprint. Already, however, already in a sibling or "distant relatives" such as aunts or uncles, the kinship relationship of the genetic profiles is hardly obvious.

As one of the pioneers of the microsatellite analysis is concerned, Dr. Ferdinand Sprinklers at the Klosterneuburg Viticulture Institute (Lower Austria) since the 1990s closely with the characterization of grape varieties. In a database contains data from over 450 varieties and 1,200 genotypes. Meanwhile, the world worked on the genetic characterization of the national grape sources, the fingerprints of the 7,000 accessions of the world's largest Rebsortiments in Vassal, Montpellier have been analyzed. The analytical results are compared in a central European varieties database and summarized (see also VIVC ).

In the Breeding resistant varieties of modern use is made ​​more recently the manipulative Genetic Engineering . In this regard, the international project IGGP (International Grape Genome Program) started. In tissue culture suspensions may be alien resistance genes with desired properties ( Resistance against Mushrooms , Viruses or animal pests such as the Phylloxera ) Into the genome of plant cells of certain conventional varieties. From the genetically modified cells can regenerate vines, this time representing a new species, but the genetic properties of the selected species have essentially maintained, but supplemented by the "enhancing" smuggled alien genes.

The hoped-for effects were, however, in practice most were satisfactory or not. In woody plants, it is not enough apparently, individual genes simply somewhere to infiltrate into the genome and to hope that such a complex and environmentally dependent properties such as the stamping of fungal resistance may have. To what extent this technology in terms of effort and result in the cost of the vine at all to the success and practical application is currently not foreseeable and not in great demand. In any case, the introduction of genetically engineered varieties clones to further depletion of species and to further reduce the Klonvielfalt to a few Clone . lead Whether these artificially manipulated and distorted vines in their genetic balance of mass Vegetative propagation prove stable in the long term as one can still not be answered seriously.

DNA analysis in wines today are increasingly used with great success to Wine adulteration (Pantschereien) track. Researchers from the Institute INRA Montpellier in 2002, a method for isolating DNA from wine and must have developed, with which one can distinguish pure-grade quality of inexpensive wine blends. So far, the methodology is so advanced that you can find on the basis of unfiltered wine varietal fingerprinting, whether a wine varietal grapes vinified purely from the specified or if Most other grape varieties were included. A quantitative determination of the proportions of the different varieties of wine is not (yet) possible, but certainly can be reconstructed, which varieties are present in the wine.

So far, the INRA team has identified the genetic profiles of 600 grape varieties wines. In bottled wines, the method will not yet, because in the course of the filtering process the majority of the DNA Is (DNS) are filtered and the residual concentration is too low to residual DNA in the finished wine for the genetic analysis. The research goes further, however intense. Using the method PNA-FISH can be established microbiologically Wine error such as Horse sweat be detected. See also Nuclear Magnetic Resonance and Certification of vines .