Search results
By finding recombination frequencies for many gene pairs, we can make linkage maps that show the order and relative distances of the genes on the chromosome.
Figure 11.2.2 A typical and simple gene map shows the relative distances among three genes, A, B and C. The distance between genes A and B is shown as 8 map units, the distance between genes B and C is shown as 12 map units, and therefore the distance between genes A and C is 20 map units.
20 cze 2023 · A particularly efficient method of mapping three genes at once is the three-point cross, which allows the order and distance between three potentially linked genes to be determined in a single cross experiment (Figure \(\PageIndex{12}\)). This is particularly useful when mapping a new mutation with an unknown location to two previously mapped loci.
Calculate the map distance between loci given the phenotypes of offspring or predict phenotypes of offspring given the recombination frequency between loci. Use the distance to construct genetic maps based on data from two-point or three-point testcrosses.
The recombination frequency is therefore a measure of the distance between two genes. If you work out the recombination frequencies for different pairs of genes, you can construct a map of their relative positions on the chromosome (Figure 5.17).
20 cze 2023 · A genetic map shows the map distance, in cM, that separates any two loci, and the position of these loci relative to all other mapped loci. The genetic map distance is roughly proportional to the physical distance, i.e. the amount of DNA between two loci. For example, in Arabidopsis, 1.0 cM corresponds to approximately 150,000bp and contains ...
A genetic linkage map describes the position of a species' or experimental population's known genes or genetic markers in terms of recombination frequency rather than a particular physical distance along each chromosome. A linkage map is a graph that shows how frequently markers recombine during homologous chromosome crossover.
