Sickle Cell Disease

1 collaborator

Firat Soylu (Author)

WHAT IS IT?

[Heterozygote advantage] [http://en.wikipedia.org/wiki/Heterozygous_advantage] [Overdominance] [http://en.wikipedia.org/wiki/Overdominance]

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HOW IT WORKS

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HOW TO USE IT

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THINGS TO NOTICE

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THINGS TO TRY

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EXTENDING THE MODEL

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NETLOGO FEATURES

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RELATED MODELS

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CREDITS AND REFERENCES

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Comments and Questions

Joseph Ferguson

question about model (Question)

Hi Firat, I am Interested in your sickle cell anemia model. I am also interested in modelling evolution in the context of disease in humans. I cannot seem to get the mutation events to take place in your model. Any ideas as to how to go about fixing this? Cheers, Joseph

Posted almost 11 years ago

Click to Run Model

breed [humans human]
humans-own [first-allele second-allele age isMalaria?]

to setup
  clear-all
  design-humans
  set-default-shape humans "person"
  ask patches [
    if pycor >= 1 [set pcolor (scale-color green region1-swampiness 10 0)]
    if pycor <= -1 [set pcolor (scale-color green region2-swampiness 10 0)]
    if (pycor > -1 and pycor < 1) [ set pcolor grey ] 
    ]
  reset-ticks
end 

to design-humans
  create-humans initial-population [
    randomly-locate ifelse-value (random-float 1 > 0.5) [1] [2] ;region 1 or region 2
    set first-allele "S"
    set second-allele "S"
    set age random 20
    set color blue
  ]
end 

to randomly-locate [region]
  setxy (ifelse-value (random-float 1 > 0.5) [random-float max-pxcor - 1] [random-float min-pxcor + 1]) (ifelse-value (region = 1) [1 + random-float (max-pycor - 1)] [ -1 + random-float (min-pycor + 1)])
end 

to go
  if count humans < min-population or count humans > max-population [stop]
  ask humans [
    check-if-sick
    set age age + 1
    if  age > 100 or (isMalaria? = true and random-float 100 < malaria-dead-probability) or (shape = "person sick" and random-float 100 < sicklecell-dead-probability) [die]
    if (random-float 100 < malaria-probability-coefficient * (1 / (pcolor - 49))) and shape = "person" [set isMalaria? true set color red]
    move
  ]
    repeat round (count humans * reproduction-rate / 200) [
      ask one-of humans  [
        if any? other humans [
          ask one-of other humans [
            reproduce]
        ]
      ]
    ]   
  tick
end 

to reproduce
  hatch 1 [ 
    set first-allele ifelse-value (random 1 < 0.5) [[first-allele] of self] [[second-allele] of self] ;mother
    set second-allele ifelse-value (random 1 < 0.5) [[first-allele] of myself] [[second-allele] of myself] ;father
    set age 0
    check-if-sick
    randomly-locate ifelse-value (ycor > 0) [1] [2]
  ]
end 

to move
  if (abs [pxcor] of patch-ahead 0.1) + 1 > max-pxcor [ set heading (- heading) ]
  if ((abs [pycor] of patch-ahead 0.1) + 1 > max-pycor) or ((abs [pycor] of patch-ahead 0.1) - 1 < 0) [ set heading (180 - heading) ]
  fd 0.1
end 

to mutate [human-set]
  ask one-of human-set [
    ifelse random-float 1 > 0.5 [set first-allele "s"] [set second-allele "s"]
    check-if-sick
    ]
end 

to check-if-sick
    let current-color color
    ifelse first-allele = "s" and second-allele = "s" [set shape "person sick"] 
    [ifelse first-allele = "s" or second-allele = "s" [set shape "person carrier"] [set shape "person"]]
    set color current-color
end

There is only one version of this model, created about 11 years ago by Firat Soylu.

Attached files

File	Type	Description	Last updated
Sickle Cell Disease.png	preview	Preview for 'Sickle Cell Disease'	about 11 years ago, by Firat Soylu	Download

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