Single recombinants | Double recombinants | ||||||
---|---|---|---|---|---|---|---|
Non recombinants | Non- NOR arm | NOR arm | One per arm | Two in non-NOR arm | |||
Observed nos. | 59 | 53 | 18 | 15 | 3 | ||
71 | 18 | ||||||
Expected nos. (no chromatid interference) | 54.76 | 52.8 | 21.2 | 19.24 | 0 | ||
74 | 19.24 | ||||||
Expected nos. (chromatid interference) | 35.5 | 112.7 | 0 |
Shown are the observed numbers of nonrecombinant and recombinant chromosomes in the BC_{2} population of 148 plants and the arm locations of the recombination site. Also shown are the expected numbers of nonrecombinant and recombinant chromosomes with a BC_{2} population of 148 plants based on the observed frequencies of rod and ring bivalents without and with complete chromatid interference. An example of expected numbers calculation for single recombinants (no chromatid interference) is as follows:
1. Rods:rings, 48%:52%.
2. Rods = 50% nonrecombinants and 50% single recombinants (see Figure 1). Therefore in total population 24% = single recombinants.
3. Rings = 25% nonrecombinants, 50% single recombinants and 25% double recombinants (see Figure 1). Therefore in total population 26% = single recombinants.
4. 24% + 26% = 50% single recombinants = 74 plants out of the 148.