Skip to main content

Table 2 Evaluation of the Chi-square test statistic (χ2) for fit of observed data to expectations under alternative quantitative genetic models.

From: Retention of low-fitness genotypes over six decades of admixture between native and introduced tiger salamanders

Trait

Model

χ 2

P Λ

Mass

μ 0

28.384

0.0080

NA

 

μ0 + bS*

5.979

0.9171

0.0000

 

μ0 + bS + bH

5.917

0.8788

0.8038

 

μ0 + bS + bH + bSS

5.533

0.8528

0.5357

 

μ0 + bS + bH + bSS + bHH

4.791

0.8522

0.3888

 

μ0 + bS + bH + bSS + bHH + bSH

4.157

0.8427

0.4262

SVL

μ 0

8.714

0.7942

NA

 

μ0 + bS*

2.163

0.9991

0.0105

 

μ0 + bS + bH

2.129

0.9980

0.8530

 

μ0 + bS + bH + bSS

2.042

0.9960

0.7688

 

μ0 + bS + bH + bSS + bHH

1.795

0.9943

0.6193

 

μ0 + bS + bH + bSS + bHH + bSH

1.527

0.9923

0.6042

Tmet

μ 0

45.252

0.0000

NA

 

μ0 + bS

36.341

0.0003

0.0028

 

μ0 + bS + bH*

17.657

0.0899

0.0000

 

μ0 + bS + bH + bSS

17.163

0.0708

0.4821

 

μ0 + bS + bH + bSS + bHH

16.781

0.0523

0.5368

 

μ0 + bS + bH + bSS + bHH + bSH

16.782

0.0325

1.0000

Growth

μ 0

6.568

0.9230

NA

 

μ0 + bS*

1.316

0.9999

0.0219

 

μ0 + bS + bH

1.317

0.9998

1.0000

 

μ0 + bS + bH + bSS

1.137

0.9997

0.6720

 

μ0 + bS + bH + bSS + bHH

0.968

0.9995

0.6811

 

μ0 + bS + bH + bSS + bHH + bSH

0.757

0.9994

0.6457

  1. The first model (including only μ0) is a null model of no variation among cross types. Significant chi-square values ( < 0.05) indicate lack of fit relative to a saturated model. Significant (PΛ < 0.05) likelihood-ratio tests (Eq. 2) indicate improvement in fit of higher-order models over simpler models. Asterisks denote the best-fit model for each phenotype.