Table I.
Comparison of length values (μm) for the mitotic metaphase chromosomes and SCs of sorghum
| Chromosmed | Metaphase, Gu et al. (1984)a
|
Metaphase, Yu et al. (1991)b
|
SC (Bivalent)c
|
|||
|---|---|---|---|---|---|---|
| Mean length | Relative length | Mean length | Relative length | Mean length | Relative length | |
| % | % | % | ||||
| 1 | 5.6 ± 0.06 | 17.17 | 4.80 ± 0.36 | 16.79 | 29.73 ± 1.19 | 15.34 |
| 2 | 4.16 ± 0.05 | 12.76 | 4.04 ± 0.33 | 14.13 | 24.77 ± 0.93 | 12.78 |
| 3 | 3.77 ± 0.10 | 11.56 | 3.38 ± 0.30 | 11.82 | 22.31 ± 0.73 | 11.51 |
| 4 | 3.34 ± 0.01 | 10.24 | 2.98 ± 0.21 | 10.42 | 20.65 ± 0.91 | 10.65 |
| 5 | 3.02 ± 0.05 | 9.26 | 2.75 ± 0.12 | 9.62 | 17.74 ± 0.71 | 9.15 |
| 6 | 2.77 ± 0.03 | 8.49 | 2.57 ± 0.13 | 8.99 | 16.94 ± 0.581 | 8.74 |
| 7 | 2.64 ± 0.10 | 8.10 | 2.30 ± 0.08 | 8.04 | 16.46 ± 0.62 | 8.49 |
| 8 | 2.55 ± 0.12 | 7.82 | 2.12 ± 0.18 | 7.42 | 15.95 ± 0.67 | 8.23 |
| 9 | 2.49 ± 0.08 | 7.64 | 1.93 ± 0.28 | 6.75 | 15.24 ± 0.63 | 7.86 |
| 10 | 2.27 ± 0.13 | 6.96 | 1.72 ± 0.13 | 6.02 | 14.07 ± 0.67 | 7.26 |
| Set lengthe | 32.61 | – | 28.59 | – | 193.87 | – |
Mean SC set length ÷ mean metaphase set length from Gu et al. (1984) = 5.95. Mean SC set length ÷ mean metaphase set length from Yu et al. (1991) = 6.78.
Length data are from Gu et al. (1984). The no. of sets from which measurements were taken is listed as four to six.
Length data are from Yu et al. (1991). Five chromosome sets were measured.
Values are based on measurement of 11 complete SC sets.
For each SC set, the 10 bivalents were assigned a no. based on relative length (with “1” being the longest). For “chromosome 1”, the mean length was the average of the longest chromosome in each of the 11 SC sets examined, the mean length of “chromosome 2” was the average of the second-longest SC from each of the 11 SC sets, etc. Whether a particular SC always maintains a consistent relative length to the other SCs in a set has yet to be determined. Chromosome nos. assigned to mitotic metaphase chromosomes also reflect relative length, although other factors including relative arm ratio and C banding were used to differentiate chromosomes. It is possible that SC length and mitotic metaphase chromosome length are not directly correlated (e.g. metaphase chromosome 5 may actually contain the same linkage group as SC 9, etc.).
Average length of a complete (1C) chromosome set.