Table 2.
In vitro sperm competition assays.
| Assay type1 | Ova donor2 | Sperm donor2 | 2-pronuclei ova | P (Dyed) | P3 | Conspecific precedence4 | ||
|---|---|---|---|---|---|---|---|---|
| Dyed | Not | Dyed | Not | |||||
| (A) Inbred-derived females and males | ||||||||
| Control | DOM (31) | DOM (8) | DOM (8) | 131 | 124 | 0.51 | 10−11 | −0.55 |
| Competitive | DOM (36) | “ | MUS (9) | 67 | 221 | 0.23 | ||
| Control | DOM (9) | MUS (2) | MUS (2) | 54 | 56 | 0.49 | 10−7 | 0.59 |
| Competitive | DOM (23) | “ | DOM (5) | 150 | 42 | 0.78 | ||
| Control | MUS (19) | DOM (8) | DOM (8) | 141 | 186 | 0.43 | 10−9 | −0.48 |
| Competitive | MUS (33) | “ | MUS (11) | 93 | 319 | 0.23 | ||
| Control | MUS (8) | MUS (5) | MUS (5) | 96 | 137 | 0.41 | 10−6 | 0.47 |
| Competitive | MUS (19) | “ | DOM (7) | 187 | 121 | 0.61 | ||
| (B) MUS females, MUS and wild-derived males | ||||||||
| Control | MUS (3) | MUS (1) | MUS (1) | 34 | 42 | 0.45 | 10−17 | 1.15 |
| Competitive | MUS (6) | “ | DOMWILD (1) | 122 | 5 | 0.96 | ||
1
Control: Dyed sperm from a male was competed against undyed sperm from the same male. Competitive: This same dyed sperm was competed against undyed sperm from a second male.
2
Numbers in parentheses indicate the number of individual mice sampled.
3
Fisher’s exact test probability of independence between the number of ova fertilized or not, comparing each pair of rows.
4
The shift in the proportion of dyed ova between control and competitive experiments. For example, from the first two rows, conspecific precedence=(0.23–0.51)/0.51=−0.55, suggesting dyed DOM sperm performs 55% worse than expected when in competition with undyed MUS sperm.