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3D view of the created Individual-based Model (IbM) to study 
human skin pigmentation




2D view of the extended Individual-based Model (IbM) which enables to simulate the evolution of any Mendelian inheritance trait

Analyses and Simulation of Human Skin Pigmentation Developing an Individual-Based Model (IbM)

GLÒRIA MACIÀ MUÑOZ

On 20th July 2010 a blonde-haired, blue-eyed white baby was born from a black Nigerian couple with no known white ancestry, who already had two black children. Regarding this unusual case, the aim of this paper is to find a scientific explanation for the birth of a fair-skinned descendant from two Sub-Saharan African individuals. Ruled out infidelity, three hypotheses are proposed:


(I) A certain type of albinism, a rare genetic disorder which causes hypopigmentation.

(II) The presence of white skin alleles, coming from a long forgotten interracial coupling, in the parents DNA.

(III) A unique genetic mutation never seen before.


 First of all, this research studies melanogenesis in order to determine the key genes involved in it. Then, the hypotheses are evaluated separately, fixing, for each one, a probability which is discussed and associated with its phenotypic consequences. Finally, following the ODD protocol, it has been written an Individual-based Model to compare the theoretical results. This innovative methodology, already evaluated in ecology and microbiology, proves to be useful, as well, in population genetics. Consequently, a new approach to this field is plausible. Furthermore, the created program allows the user not only to observe the progressive genotypic and phenotypic evolution of skin pigmentation in his/her Sub-Saharan African population, but also of any population in the world. Lastly, the model code is extended to enable it to simulate the evolution of any Mendelian inheritance trait.