Table 1.
D. melanogaster Inbred Lines from Three Distinct Regions Show Elevated Cold Tolerance (Measured as the Percentage of Female Flies Still Standing or Moving After 96 h at 4 °C).
| Altitude | Midpoint | Min. Month | Lines | Mobility, | Standard | U Test | |||
|---|---|---|---|---|---|---|---|---|---|
| Population Sample | Genomes | Latitude | (meters) | Temperature (°C) | Low (°C) | Tested | 96 h at 4 °C | Deviation | P Value |
| Siavonga, Zambia (ZI) | 197 | −16.5 | 530 | 25 | 12 | 0 | – | – | |
| Phalaborwa, S. Africa (SP) | 37 | −23.9 | 350 | 22 | 8 | 19 | 26.8% | 26.1% | 0.0007 |
| Dullstroom, S. Africa (SD) | 81 | −25.4 | 2000 | 13 | 1 | 50 | 48.8% | 23.8% | |
| Gambella, Ethiopia (EA) | 24 | 8.2 | 525 | 28 | 20 | 9 | 13.1% | 9.6% | 0.0003 |
| Fiche, Ethiopia (EF) | 69 | 9.8 | 3070 | 11 | 2 | 46 | 36.3% | 20.4% | |
| Cairo, Egypt (EG) | 32 | 30.1 | 25 | 22 | 8 | 24 | 28.0% | 26.4% | <0.0001 |
| Lyon, France (FR) | 96 | 45.8 | 175 | 12 | −1 | 67 | 82.9% | 12.9% |
To illustrate climate differences, estimates of the “midpoint temperature” (the average of 24 monthly average highs and lows) and the minimum monthly average low are given. Mann-Whitney P values show that within each pair of populations, the sample originating from the higher altitude/latitude shows significantly greater cold tolerance.