TABLE 1.
Association frequencies of homologous chromosome arm territories in differentiated and meristematic tissues of A. thaliana seedlings
| Whole A. thaliana seedling |
SCD model (n = 103) |
Flow-sorted nuclei: | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Association frequency (%) |
Association frequency (%) |
|||||||||||||
| Homologs | Organ | Cell type | Nuclei shape | n | T+B+ | T+B− | T−B+ | T−B− | T+B+ | T+B− | T−B+ | T−B− | χ2 testa | χ2 testa |
| AT1 | Cotyledon | Vascular | Rod | 100 | 32.0 | 15.0 | 13.0 | 40.0 | 23.6 | 9.1 | 10.3 | 57.0 | * | – |
| Cortical and epidermal | Spindle | 100 | 51.0 | 16.0 | 10.0 | 23.0 | 48.2 | 10.8 | 11.6 | 29.4 | – | – | ||
| Spherical | 100 | 53.0 | 12.0 | 14.0 | 21.0 | 59.9 | 13.1 | 14.9 | 12.1 | – | – | |||
| Guard | Spherical | 100 | 50.0 | 16.0 | 18.0 | 16.0 | 59.9 | 13.1 | 14.9 | 12.1 | – | * | ||
| Shoot | Meristematic | 100 | 38.0 | 16.0 | 21.0 | 25.0 | 43.9 | 11.0 | 12.3 | 32.8 | –b | |||
| Stem | Vascular | Rod | 100 | 36.0 | 10.0 | 11.0 | 43.0 | 23.6 | 9.1 | 10.3 | 57.0 | – | ||
| Cortical and epidermal | Spindle | 100 | 46.0 | 15.0 | 15.0 | 24.0 | 48.2 | 10.8 | 11.6 | 29.4 | – | |||
| Spherical | 100 | 49.0 | 11.0 | 17.0 | 23.0 | 59.9 | 13.1 | 14.9 | 12.1 | – | ||||
| Root | Vascular | Rod | 100 | 29.0 | 16.0 | 10.0 | 45.0 | 23.6 | 9.1 | 10.3 | 57.0 | * | – | |
| Cortical and epidermal | Spindle | 100 | 44.0 | 14.0 | 17.0 | 25.0 | 48.2 | 10.8 | 11.6 | 29.4 | – | – | ||
| Spherical | 100 | 50.0 | 11.0 | 18.0 | 21.0 | 59.9 | 13.1 | 14.9 | 12.1 | * | – | |||
| Root hair | Spindle | 36 | 25.0 | 13.9 | 11.1 | 50.0 | 48.2 | 10.8 | 11.6 | 29.4 | – | – | ||
| Meristematic | 100 | 45.0 | 15.0 | 17.0 | 23.0 | 43.9 | 11.0 | 12.3 | 32.8 | –b | ||||
| AT2 | Cotyledon | Vascular | Rod | 100 | 26.0 | 9.0 | 31.0 | 34.0 | 18.7 | 1.8 | 21.1 | 58.4 | *** | – |
| Cortical and epidermal | Spindle | 100 | 36.0 | 9.0 | 18.0 | 37.0 | 26.3 | 1.8 | 33.2 | 38.7 | *** | – | ||
| Spherical | 100 | 47.0 | 11.0 | 22.0 | 20.0 | 39.1 | 3.3 | 43.6 | 21.2 | *** | – | |||
| Guard | Spherical | 100 | 50.0 | 13.0 | 10.0 | 27.0 | 39.1 | 3.3 | 43.6 | 21.2 | *** | – | ||
| Shoot | Meristematic | 120 | 34.2 | 15.8 | 9.2 | 40.8 | 28.0 | 2.3 | 32.6 | 39.4 | ***b | |||
| Stem | Vascular | Rod | 100 | 26.0 | 9.0 | 24.0 | 41.0 | 18.7 | 1.8 | 21.1 | 58.4 | *** | ||
| Cortical and epidermal | Spindle | 100 | 44.0 | 9.0 | 18.0 | 29.0 | 26.3 | 1.8 | 33.2 | 38.7 | *** | |||
| Spherical | 100 | 41.0 | 12.0 | 20.0 | 27.0 | 39.1 | 3.3 | 43.6 | 21.2 | ** | ||||
| Root | Vascular | Rod | 100 | 26.0 | 10.0 | 22.0 | 42.0 | 18.7 | 1.8 | 21.1 | 58.4 | *** | ||
| Cortical and epidermal | Spindle | 100 | 43.0 | 5.0 | 19.0 | 33.0 | 26.3 | 1.8 | 33.2 | 38.7 | *** | |||
| Spherical | 100 | 46.0 | 7.0 | 25.0 | 22.0 | 39.1 | 3.3 | 43.6 | 21.2 | ** | ||||
| Root hair | Spindle | 29 | 41.4 | 13.8 | 24.1 | 20.7 | 26.3 | 1.8 | 33.2 | 38.7 | *** | |||
| Meristematic | 120 | 31.7 | 11.0 | 19.0 | 38.3 | 28.0 | 2.3 | 32.6 | 39.4 | ***b | ||||
Simulated and flow-sorted leaf or root nuclei classified according to their shapes (Pecinka et al. 2004) in comparison to whole-mount FISH data. T, top arm, B, bottom arm, +, associated, −, separated. For individual columns under “Whole A. thaliana seedling” and “SCD model”: regular type, P > 0.05; italic type, P < 0.05; underlined type, P < 0.01; boldface type, P < 0.001.
Significance level of differences between the entirety of observed association frequencies in whole-mount seedlings vs. the random expectation for the corresponding nuclear shape or vs. corresponding frequencies in flow-sorted nuclei in a column-wise comparison: –, P > 0.05; *P < 0.05; **P < 0.01; ***P < 0.001.
Association frequencies in meristematic cells were compared to the random association frequency of homologous chromosome arm territories calculated as an average of predicted association values for spherical-, spindle-, and rod-shaped nuclei.