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Table 2 Codon-based Z-test of selection for analysis averaging over all sequence pairs. Alternative hypotheses of neutrality, positive selection and purifying selection were tested for each population as well as for the total dataset of Carcinus aestuarii. For each population, examined specimens were assigned to the corresponding Cox1 type

From: Parapatric genetic divergence among deep evolutionary lineages in the Mediterranean green crab, Carcinus aestuarii (Brachyura, Portunoidea, Carcinidae), accounts for a sharp phylogeographic break in the Eastern Mediterranean

Population Number of specimens Cox1 Type Lack of neutral evolution (dN=/=dS) Positive selection (dN > dS) Purifying selection (dN < dS)
I II III Test statistic (dN-dS) P value Test statistic (dN-dS) P value Test statistic (dS-dN) P value
Tabarka 10 10 −2.381 0.019 −2.509 1.000 2.403 0.009
Bizerte 15 15 −2.409 0.018 −2.371 1.000 2.386 0.009
Sidi Rais 11 10 1 −4.545 0.000 −4.538 1.000 4.631 0.000
Kelibia 10 10 −2.417 0.017 −2.549 1.000 2.478 0.007
Benikhiar 12 12 −0.979 0.330 −1.007 1.000 1.010 0.157
Monastir 11 9 2 −5.284 0.000 −5.271 1.000 5.274 0.000
Chebba 12 9 3 −5.580 0.000 −5.671 1.000 5.645 0.000
Sfax 15 5 10 −5.035 0.000 −5.045 1.000 5.090 0.000
Djerba 14 8 6 −5.121 0.000 −5.145 1.000 5.172 0.000
Tripoli 11 10 1 −4.672 0.000 −4.755 1.000 4.818 0.000
Mosrata 12 9 3 − 5.216 0.000 − 5.169 1.000 5.246 0.000
Venice Lagoon 11 11 −3.126 0.002 −3.105 1.000 3.317 0.001
Pomer 20 20 −4.108 0.000 −4.064 1.000 4.213 0.000
Amvrakikos 13 13 −3.480 0.001 −3.554 1.000 3.514 0.000
Lefkada 14 13 1 −5.091 0.000 −5.108 1.000 4.886 0.000
Navarino 10 6 4 −5.234 0.000 −5.097 1.000 4.919 0.000
Alexandroupolis 12 12 −4.282 0.000 −4.209 1.000 4.190 0.000
Izmir Bay 6 6 −2.023 0.045 −2.089 1.000 2.084 0.020
Enez Dalyan Lagoon 20 20 −4.541 0.000 − 4.577 1.000 4.540 0.000
Dardanelles Strait 5 5 −3.547 0.001 −3.566 1.000 3.665 0.000
Prince’s Islands 12 12 −3.766 0.000 −3.659 1.000 3.739 0.000
Bosphorus Strait 7 7 −2.649 0.009 −2.599 1.000 2.626 0.005
Total 263 170 26 67 −6.224 0.000 −6.013 1.000 6.256 0.000
  1. For each test hypothesis, the probability of rejecting the null hypothesis of strict-neutrality (dN = dS) as well as the probability of rejecting the null hypothesis of strict-neutrality (dN = dS) in favor of the alternative hypothesis of positive selection (dN > dS) or purifying selection (dN < dS) were expressed as P values. Values of P less than 0.05 are considered significant. dS and dN are the numbers of synonymous and nonsynonymous substitutions per site, respectively