Search results
[1/2 * (TT – 2NPD) + 4NPD] / (PD + TT + NPD) = frequency of recombination or (1/2 * TT + 3NPD) / (PD + TT + NPD) = frequency of recombination Finally, the map equal the recombination frequency times 100: (1/2 * TT + 3NPD) / (total tetrads) * 100 = map distance (centimorgans)
Map distance = (total rec. events / total tetrads) x 100 = [(1/2[SCO] + DCO) / total tetrads] x 100 Map distance = ([1/2 (T – 2 NPD) + 4 NPD]/ total tetrads) x 100 Map distance = (1/2 T + 3 NPD) / total tetrads x 100
Map distance = ([1/2 (T – 2 NPD) + 4 NPD]/ total tetrads) x 100 Map distance = (1/2 T + 3 NPD) / total tetrads x 100 For our example above, map distance = ([1/2 (70) + 3 (3)] / 200) x 100 = 22 map units
Step 1: Calculate the recombination frequency: Recombination Frequency (RF) = Number of recombinant offspring / Total number of offspring. RF = 150 / 1000 = 0.15. Step 2: Convert recombination frequency to map distance: Map Distance (cM) = RF × 100. Map Distance = 0.15 × 100 = 15 cM.
1 wrz 2000 · Each marker allele can be represented by a “1” or “0,” making it possible to calculate PD, NPD, and TT frequencies quickly for any pair of markers (Fig. 2C). The frequencies of these classes can then be used with the mapping functions described above to determine genetic map distances.
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.
The map distance between two linked genes are calculated according to the following formula: cM = 50 * (TT + 6 * NPD) / ( PD + NPD + TT ). Here PD stands for parental ditype, NPD stands for non-parental ditype, and TT stands for tetratype. PD, NPD, and TT are calculated from the ascus genetic patterns. Ordered tetrads with four spores
