Table 1.
Chromosome axis lengths and chromatin extension in PARs and distal ends of Chr 18 and 19.
| A. DNA content vs. chromosome axis lengths (late zygonema) | |||||
|---|---|---|---|---|---|
| Chromosome | Total size (Mb) | Probe-distal region (Mb) | Total chromosome axis (μm)a | Probe-distal axis (μm)a | DNA content of probe- distal axis (Mb/μm) |
| Y | 95 | 0.7 | 4.2 ± 0.7 (17) | 0.7 ± 0.2 (20) | 1 |
| X | 167 | 0.7 | 12.7 ± 2.8 (13) | 0.8 ± 0.2 (23) | 1 |
| 18 | 91 | 8 | 6.1 ± 0.9 (11) | 0.6 ± 0.1 (12) | 13 |
| 19 | 61 | 6 | 5.1 ± 0.5 (11) | 0.6 ± 0.1 (10) | 10 |
| B. Length of chromatin extension from axes | |||||
|---|---|---|---|---|---|
| Locus | Probe size (kb)b | FISH signal extension, mean μm ± SD (number of observations)
|
|||
| Leptonema | Early/mid-zygonema | Late zygonema | Pachynema | ||
| Y PAR | 146 | 0.5 ± 0.2 (25) | 0.6 ± 0.3 (21) | 0.6 ± 0.3 (21) | 1.2 ± 0.5 (23)c |
| X PAR | 0.6 ± 0.4 (23) | 0.7 ± 0.5 (17) | 0.6 ± 0.5 (20) | ||
| Distal Chr 18 | 207 | 2.2 ± 0.8 (26) | 3.2 ± 1.5 (31)c | 4.5 ± 1.9 (35)c | 5.4 ± 2.2 (21)c |
| Distal Chr 19 | 182 | 2.3 ± 0.9 (18) | 3.6 ± 2.0 (33)c | 5.3 ± 3.0 (40)c | 5.9 ± 2.3 (23)c |
a
mean ± SD (number of observations)
b
size of BAC
c
some or all measurements are from paired FISH signals