TABLE 3.
Zygotic morphology and budding
| Matinga | Time (h) | % Zygotesb | % of zygotesc that were:
|
|
|---|---|---|---|---|
| Abnormal | Budded | |||
| MATa (wt) × MATα (wt) | 1 | 0 | ndd | nd |
| 1.5 | 1 ± 1 | nd | nd | |
| 2 | 4 ± 1 | 5 ± 3 | 21 ± 3 | |
| 2.5 | 4 ± 1 | 8 ± 1 | 39 ± 2 | |
| 3 | 5 ± 1 | 7 ± 2 | 52 ± 2 | |
| MATa (asg7Δ) × MATα (wt) | 1 | 0 | nd | nd |
| 1.5 | 1 ± 1 | nd | nd | |
| 2 | 3 ± 1 | 42 ± 7 | 2 ± 1 | |
| 2.5 | 4 ± 1 | 57 ± 2 | 9 ± 3 | |
| 3 | 5 ± 1 | 63 ± 3 | 31 ± 1 | |
Wild-type (wt) MATα cells (W303-1B) were mated on filters to either wild-type MATa cells (W303-1A) or isogenic asg7Δ MATa cells (NDY1089).
The mean percentages of the total cells within the mating mixture showing typical zygotic (dumbbell-like) morphology ± standard deviations are reported. Five hundred cells were counted from three experiments. Prezygotes are not distinguished from zygotes by this analysis and are thus included within the percent zygotes.
For each mating time point, 200 cells identified as zygotes (or prezygotes) were subclassed as having either normal or abnormal morphology and also subclassed as to whether or not they displayed a bud. Zygotes were considered morphologically abnormal if they either showed a bent morphology or displayed a bulge-like protrusion emerging from the conjugation bridge (see Fig. 6 for examples). Buds were distinguished (from bulges) by the neck-like constriction present at the emergence site. Both the percentages of total zygotes (plus prezygotes) that were considered to be morphologically abnormal and the percentages that displayed obvious buds were determined for three experiments with the means ± the standard deviations being reported. As some zygotes with small buds certainly escaped detection, the percentages of zygotes with buds reported are likely to be underestimates.
nd, not determined.