Table 2

Estimates of parameters of the demographic model applied to Cross River and western lowland gorillas

Prior distribution

min

max

Posterior mode

HDI 50b

HDI 90b

HDI 95b


2Nm

Loguniform

1

15.85

9.55

[4.57, 13.8]

[1.58, 15.84]

[1.32, 15.85]

Ncrossriver_old/Ncrossriver_now)

Loguniform

1

100

61.7

[33.1, 93.3]

[10, 100]

[4.2, 100]

Ncrossriver_now

N(200, 100) a

68

300

271

[223, 292]

[146, 300]

[122, 300]

Nancestral

Uniform

500

25,000

2,547

[1,383, 4,032]

[500, 6,681]

[500, 7,684]

Nwestern

N(24,000, 5000) a

10,000

30,000

22,376

[18,765, 25,319]

[14,217, 28,930]

[12,879, 29,532]

Tdivergence

Loguniform

10

3,162

891

[269, 1,738]

[60.3, 3,090]

[38, 3.162]

Tbottleneck

Loguniform

10

316

16

[33.1, 93.3]

[10, 97.7]

[10, 141]

Tmigration

Loguniform

10

3,162

21

[11.7, 60.3]

[10, 446.7]

[10, 812]


Ncrossriver_now, Nancestral, Nwestern represent the effective population sizes of Cross River, ancestral and western lowland gorillas respectively. Timings in generations were estimated on the log10 scale and indicate the divergence (Tdivergence), the onset of the bottleneck (Tbottlneck) and the cessation of migration (Tmigration). The number of diploid individuals exchanged between the populations was also estimated on the log10 scale as 2 Nm. For parameters estimated on the log10 scale we chose uniform priors on the same scale.

a Corresponds to a normal distribution of the form N(μ, σ) truncated at [min, max]

b The high posterior density interval HDI is chosen as the smallest continuous interval spanning 50% of the posterior surface. The other HDI are chosen accordingly.

Thalmann et al. BMC Evolutionary Biology 2011 11:85   doi:10.1186/1471-2148-11-85

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