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Biotechnology

See under molecular genetics.

Term for a branch of molecular biology used to study the structure of the genome (the entirety of the genetic material in an organism) and the function and interaction of genes (the hereditary factors located on the DNA strand in the chromosomes of each cell nucleus). Genetic engineering or Genetic engineering is the application of genetic methods in practice and usually means the artificial manipulation of genes with the aim of introducing desired, hitherto non-existent properties, such as resistance to fungal diseases, into an existing organism through the technically feasible implantation of individual replicated foreign genes from organisms foreign to the species into the genome of a variety or breed.

Molekulargenetik - DNA-Stränge

Polymerase Chain Reaction

Since the invention of the PCR method (Polymerase Chain Reaction) for amplifying minute amounts of DNA in the 1990s, grapevine varieties can now also be clearly characterised, defined and recognised as varieties genotypically with the help of molecular genetic characterisation methods. This introduced the genotype into ampelography, which, as a complement to the traditional, visually phenotype-based ampelography, can help to clarify many still unanswered questions. Each distinct grapevine germinated from a seed is represented by a distinctive genotype, characterised by the unique recombination of maternal and paternal genetic material during fertilisation and present in the nucleus of each plant cell. Each grapevine variety resulting from sexual reproduction has an individual genetic pattern that distinguishes it from all other grapevine varieties.

Microsatellite analysis

For genotypic comparisons or the identification of grapevine varieties as well as the determination of the parent pair, the so-called genetic fingerprint is used, which can be created with a microsatellite analysis. The microsatellites are retraceable areas within the long DNA chain defined by molecular markers, which have a different number of repeating base sequences. These sequences, which are repeated twice in the given double chromosome set of the grapevine (2n = 38), can be of different length between two homologous chromosomes as well as from grapevine variety to grapevine variety. One can copy and duplicate these sequences as single fragments, so that one obtains a certain characteristic by the length of these genome fragments.

Many such fragments of several gene loci, always present in pairs, result in a fragment pattern that is typical of the variety and characterises this variety, which can be compared with the fragment patterns of other grape varieties. This fragment pattern is, so to speak, a genetic fingerprint. The probability that two grapevine varieties have the same pattern is statistically about 1:6 million, with only about 14,000 existing grapevine varieties and breeding strains a vanishingly small probability. Within the European grapevine breeding institutes there is an agreement that for the genotypic characterisation of grapevine varieties it is sufficient to determine the genotype at six defined gene loci (microsatellites) in order to clearly define the profile of a variety.

Before the method of microsatellite analysis, variety comparisons and variety delimitations were only possible via the comparative morphology (external shape) of the vine. The characteristics typical of the variety were described and an...

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