Table 1.

Chiasmata (Xta) configurations observed from diakinesis nuclei compared to chiasmata configurations predicted using all RNs on SCs or only MLH1-positive (MLH1+) RNs on SCs

		Average no. per nucleus (SD)
Chiasmata	No. nuclei	Rods*	Rings†	Total Xta‡
Observed	100	7.9 (1.8)	4.1 (1.7)	16.0 (1.8)
Predicted
All RNs	132§	7.6 (2.0)	4.4 (2.0)	16.4 (2.0)
MLH1+ RNs only	132§	9.3 (1.7)	2.6 (1.7)	14.6 (1.8)

^*Rods = bivalents with at least one chiasma (one or more RNs) in only one arm. Chromosome 2 was always counted as a rod with one chiasma in the long arm.

^†Rings = bivalents with at least one chiasma in both chromosome arms.

^‡The average total number of chiasmata observed per diakinesis nucleus is not significantly different from the value predicted using all RNs (P > 0.1, t test) but is significantly different from the value obtained using only MLH1-positive RNs (P < 0.001, t test).

^§The same 132 nuclei (each a complete set of 12 individually identified SCs) were evaluated for predicted chiasma configurations based on RN patterns.