Table 2. Distribution of bi-directional clusters on each chromosomea.
| Chromosome | Total number of loci | SA loci/total loci (%) | NOB loci/total loci (%) | Chromosome length (kb) | Coverage of SA loci/chromosome length (%) | Coverage of NOB loci/chromosome length (%) | Coverage of total loci/chromosome length (%) |
|---|---|---|---|---|---|---|---|
| 1 | 2214 | 12.9 | 6.1 | 246 128 | 8.4 | 10.1 | 42.9 |
| 2 | 1604 | 14 | 6.5 | 243 616 | 9.6 | 7.3 | 40.7 |
| 3 | 1263 | 15.3 | 8.1 | 199 344 | 12.0 | 10.1 | 43.9 |
| 4 | 980 | 12.6 | 6.9 | 191 732 | 8.5 | 7.3 | 36 |
| 5 | 1083 | 13.1 | 6.9 | 181 035 | 7.6 | 7.4 | 35.8 |
| 6 | 1151 | 12.7 | 8.2 | 170 915 | 9.5 | 10.1 | 41 |
| 7 | 1053 | 12.8 | 7.2 | 158 546 | 8.3 | 14.5 | 44 |
| 8 | 865 | 10.1 | 7.3 | 146 309 | 6.1 | 11.2 | 38.3 |
| 9 | 877 | 15.1 | 6.4 | 136 372 | 8.3 | 6.1 | 35.2 |
| 10 | 891 | 13.6 | 7.6 | 135 037 | 10.6 | 10.6 | 44.5 |
| 11 | 1250 | 13.3 | 6 | 134 483 | 8.9 | 7.8 | 40.7 |
| 12 | 1190 | 13.9 | 6.3 | 132 078 | 12.3 | 5.3 | 44.5 |
| 13 | 438 | 13 | 7.5 | 113 043 | 8.4 | 7.9 | 30.3 |
| 14 | 678 | 15.8 | 7.2 | 105 311 | 6.8 | 9.3 | 34.7 |
| 15 | 723 | 14.8 | 7.3 | 100 257 | 9.3 | 8.1 | 38.9 |
| 16 | 900 | 13.7 | 6.2 | 90 042 | 9.4 | 6.3 | 38.7 |
| 17 | 1232 | 16.4 | 4.1 | 81 860 | 14.9 | 7.3 | 50.7 |
| 18 | 388 | 10.6 | 8.2 | 76 115 | 7.6 | 10 | 38.8 |
| 19 | 1336 | 10.9 | 3.2 | 63 812 | 7.7 | 2.9 | 43.4 |
| 20 | 629 | 11.8 | 8.4 | 63 742 | 7.2 | 11 | 40.3 |
| 21 | 286 | 10.8 | 9.8 | 46 976 | 5.7 | 9.8 | 28.2 |
| 22 | 494 | 15 | 6.5 | 49 397 | 8.8 | 6.9 | 36.4 |
| X | 782 | 7.5 | 4.7 | 153 692 | 3.2 | 5.2 | 28 |
| Y | 34 | 0 | 5.9 | 50 287 | 0.0 | 0.6 | 4.5 |
| Overall | 22 341 | 13.2 | 6.5 | 3 070 128 | 8.6 | 8.4 | 38.7 |
aFor statistical significance, we used ‘Chi-square test’ to determine P-values. SA loci had a significantly (P < 0.05) higher percentage on chromosomes 3 (15.3%), 14 (15.8%) and 17 (16.4%), but a significantly lower percentage on chromosomes 8 (10.1%), 19 (10.9%), X (7.5%) and Y (0%), compared to its overall percentage (13.2%) on the whole genome; whereas, NOB loci had a significantly higher percentage on chromosomes 3 (8.1%), 6 (8.2%) and 21 (9.8%), but a significantly lower percentage on chromosomes 17 (4.1%), 19 (3.2%) and X (4.7%), compared to its overall percentage (6.5%) on the whole genome. On chromosome Y, all bi-directional cluster loci were NOB loci. Although SA loci had a significantly higher percentage (P < 10−4) than NOB loci (13.2 versus 6.5%) in overall loci, their overall coverage of chromosome length are very close (8.6 versus 8.4%), no significant difference.