TABLE 1

Predictions and tests of the meiotic drive and permissive hypotheses for knob evolution

Knob evolution hypotheses
TestsMeiotic drivePermissive
Ab10 frequency and knob index correlation+**NP
Intraspecific variability in knob sizeHigh*Low
Knob index and population size correlation+*
Knob position within chromosomal armDistal**Regions with low recombination
Knob distribution among chromosomal armsRepulsed**Random

NP, the hypothesis makes no prediction for the test.

  • * Predictions consistent with observations from Z. m. ssp. parviglumis and mexicana.

  • ** Predictions with statistical support (P < 0.05).