Table 3.
Comparison of one-rate and two-rate matrices to estimate the evolutionary correlation between three morphometric sperm traits. The evolutionary correlation coefficient r, log-likelihood (lnL) and AIC for the two models are shown.
| model | correlated traits | r | lnL | AIC |
|---|---|---|---|---|
| one-matrix model | ||||
 |
head–midpiece | 0.61 | −1286.7 | 2601.4 |
| head–flagellum | 0.59 | |||
| midpiece–flagellum | 0.79 | |||
| two-matrix model | ||||
 |
head–midpiece | 0.70 | −1229.9 | 2507.8 |
| head–flagellum | 0.62 | |||
| midpiece–flagellum | 0.85 | |||
 |
head–midpiece | −0.44 | ||
| head–flagellum | −0.66 | |||
| midpiece–flagellum | 0.30 | |||
| likelihood-ratio test | ||||
| −2 log(L1/L2)=168.1 | p(χ2, d.f. = 3) <0.0001 | |||