NetLogo User Community Models

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## WHAT IS IT?

This is a simple model of Hardy-Weinberg equilibrium and genetic drift in an ABO blood type group system. Here the organisms mate randomly and a certain phenotype can have a resistance to death after reproduction to simulate an infected population with a disease. Allele frequencies evolve purely by genetic drift.

## HOW TO USE IT

The initial-population-size slider sets the carrying capacity of the terrain. The model is initialized to have a total population of initial-population-size with the respective phenotype frequencies in each color presented on the plot.

The starting-freq-ofphenotype-A slider sets what proportion of the intial population has the A phenotype.

The starting-freq-ofphenotype-B slider sets what proportion of the intial population has the B phenotype.

The starting-freq-ofphenotype-AB slider sets what proportion of the intial population has the AB phenotype.

The starting-freq-ofphenotype-O slider sets what proportion of the intial population has the O phenotype.

The GO button runs the model.

The ONE GENERATION button simulates a single generation (single tick).

The POPULATIONS plot displays the number of individuals with the four different phenotypes: A (reds), B (blues), O (green) and AB (orange).

The monitor windows show the frequencies of the 6 different genotypes, the 3 different alleles and the 4 different phenotypes.

## THINGS TO DO

Set the carrying capacity to 14,546. Set the initial frequency of the A phenotype to 0.3, the initial frequency of the B phenotype to 0.3, the initial frequency of the AB phenotype to 0.2 and the initial frequency of the O phenotype to 0.2. Now simulate one generation. What are the resulting frequencies of the 6 genotypes?

Now run the model forward by pressing the GO button. What happens to the 6 genotypes?

Now set the initial frequency of the A phenotype to 0.1 and the initial frequency of the O phenotype to 0.4, and reset the model by pressing the SETUP button. Simulate one generation. What are the resulting frequencies of the 6 genotypes?

Now run the model forward by pressing the GO button. What happens to the 6 genotypes?

Now set the carrying capacity to 4000 and repeat the experiments above. What happens after 1 generation? What happens if you let those models run?

## EXTENDING THE MODEL

## HOW TO CITE

This model was based on the Random Mating Diploid Drift model by Carlo C. Maley and then extended by João C. Carvalho in 2023

The orinal model was based on the Simple Birth Rates model by U. Wilensky, and then extended by Carlo C. Maley in 2018.

If you mention this model or the NetLogo software in a publication, we ask that you include the citations below.

For the original model itself:

* Wilensky, U. (1997). NetLogo Simple Birth Rates model. http://ccl.northwestern.edu/netlogo/models/SimpleBirthRates. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.

Please cite the NetLogo software as:

* Wilensky, U. (1999). NetLogo. http://ccl.northwestern.edu/netlogo/. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.