Table 3.
Analysis of Leu+-containing dyads from spo13Δ diploids
| A. Analysis of unselected dyads from diploids with and without SPO13∷HO | |||||
|---|---|---|---|---|---|
| Strain | Relevant genotype | Leu+ spore-containing
dyads
|
Dyads containing only Leu− spores | Total | |
| Dyads with a single gene conversion† | Others‡ | ||||
| DAM518 | SPO11 SPO13∷HO | 13 (6%)* | 24 | 186 | 223 |
| spo11Δ SPO13∷HO | |||||
| DAM535 | SPO11 | 2 (1%) | 3 | 204 | 209 |
| spo11Δ | |||||
| B. Analysis of Leu+/Leu− dyads obtained from asci plated on growth medium | ||||||
|---|---|---|---|---|---|---|
| Strain | Relevant genotype | Analysis of ADE1–HIS4 crossing over
among Leu+-containing dyads§
|
||||
| No crossover | Crossover | % crossover | Coconversion of HIS4 | Coconversion of ADE1 | ||
| DAM518 | SPO11 | 12 | 13 | 52¶ | 1 | 0 |
| spo11Δ | ||||||
| DAM502 | spo11Δ | 30 | 11 | 27 | 5 | 3 |
| spo11Δ | ||||||
| DAM516 | SPO11 msh4Δ | 37 | 8 | 18 | 1 | 3 |
| spo11Δ msh4Δ | ||||||
| C. Analysis of unselected dyads containing a single gene conversion event | ||||||
|---|---|---|---|---|---|---|
| Strain | Genotype | Total number of dyads analyzed | Gene conversion of one spore in the
dyad
|
Among gene conversions of one spore, coconversion of HIS4‖ | Among gene conversions of one spore, coconversion of ADE1‡‡ | |
| Single gene conversion, with Leu+ spore | Single gene conversion, coconversion of leu2-R | |||||
| DAM518 | SPO11 | 223 | 13/28 (42%) | 15/28 (58%) | 3/28 (11%) | 1/9 (11%) |
| spo11Δ | ||||||
| DAM502 | spo11Δ | |||||
| spo11Δ | 344 | 4/30 (13%)** | 26/30 (87%)** | 12/30 (40%)** | 3/9 (33%) | |
Dyads in which one spore had undergone a gene conversion resulting in Leu+ phenotype while the other spore was still heterozygote for leu2-cs and leu2-R (confirmed by the ability of such diploids to give rise to Leu+ papillae).
indicates a statistically significant difference from the absence of SPO13∷HO (P < 0.01).
Dyads in which both spores undergone gene conversion events (analogous to 4∶0 tetrads) or dyads in which a Leu− spore did not give rise to Leu+ papillae because of reductional chromosomal division, chromosome missegregation, or crossing over in the interval between the LEU2 gene and the centromere.
Sectored colonies arising from the germination of two spores in an ascus were identified after germination on YEPD medium by replica plating them to medium lacking leucine. Leu+/Leu− sectored colonies were then analyzed to show that the Leu− half still retained the leu2-cs allele; hence there was a single gene conversion event in this meiosis.
Statistically significant difference from the spo11Δ strain (P < 0.05) and the msh4Δ strain (P < 0.01).
One of three His− segregants obtained from DAM518 was Leu+. The other two His− segregants obtained from DAM518 and all 12 His− segregants obtained from DAM502 were Leu−.
Indicates a statistically significant difference from the Spo11+ strain (P < 0.01).
Only a subset of events were analyzed to determine if ADE1 was heterozygous or homozygous.