Supplementary material for: Intermittent migration can induce pulses of speciation in a two-island system
Data files
Sep 27, 2023 version files 4.84 MB
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input_sea.txt
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Program_intermittent.f90
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README.md
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SM1.png
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SM2.png
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SM3.png
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supplementary.pdf
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Temporal.txt
Nov 21, 2023 version files 4.85 MB
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input_sea.txt
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Program_intermittent.f90
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README.md
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SM.pdf
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SM1.png
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SM2.png
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SM3.png
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Temporal.txt
Abstract
Geographic barriers can come and go depending on natural conditions. These fluctuations cause population cycles of expansion and contraction, introducing intermittent migrations that may not hinder speciation but rather promote diversification. Here, we study a neutral two-island speciation model with intermittent migration driven by sea-level fluctuations. Seabed depth modulates isolation and connection periods between the islands, with migration occurring during connection periods with a certain probability. Mating is restricted to genetically compatible individuals on the same island, and offspring inherit genomes from both parents through recombination. We observe speciation pulses that would not occur under strict isolation or continuous migration, with infrequent, temporary increases in species richness happening at different times depending on the combination of geographic settings and migration probability. The resulting dynamic patterns of richness exhibit contrasting behavior between connected and isolated scenarios, often including species that do not persist. Prolonged isolation can reduce richness to one species per island, resembling patterns commonly associated with archipelagos under sea-level fluctuations. Together with other studies, our results in out-of-equilibrium populations support the relevance of investigating the impact of variable migration on diversification, particularly in regions of high diversity.
README: Supplementary Material for "Intermittent migration can induce pulses of speciation in a two-island system"
supplementary.pdf contains the Supplementary Information to the manuscript.
We provide one code, written in FORTRAN: "Program_intermittent.f90"
This program has one input file, "input_sea.txt", and one output, "Temporal.txt":
a) The input\_sea.txt provides in the first line five parameters (the values in the parentheses refer to the values in the file):
a.1) Number of iterations (2000)
a.2) Initial migration probability (0.4)
a.3) Number of repetitions for the set of parameters (1)
a.4) Mutation rate (0.001)
a.5) Time interval that species identification is made (10 iterations)
The remaining lines provide the step iteration and the value of migration. The migration variation period (written over the subsequent lines) is based on the sea level data assuming a seabed of h=-50m.
Other parameters, such as minimal genetic similarity, genome size, and population size, can be adjusted in the main program.
b) The output "Temporal.txt" has 7 columns labeled as:
b.1) pop - the number of total individuals inhabiting the islands (parameter)
b.2) rep - the number of the simulation repetition (parameter)
b.3) mig - the migration rate (parameter)
b.4) tem - the time iteration; saved as multiple of (a.5)
b.5) esp - the ID of the species (initially, all individuals are conal, and their species ID is 1)
b.6) abund1 - abundance of esp on island 1 at time iteration tem
b.7) abund2 - abundance of esp on island 2 at time iteration tem