Fabio Caccioli - Santa Fe Institute #
Genetic demixing in one dimensional populations with balancing selection #
In the presence of strong competition, individuals carrying rare (genetic or phenotypic) traits may 
be able to exploit new resources, survive predation or better adapt to an evolving environment. 
In the framework of population genetics, this advantage is summarized by the concept of "balancing 
(or negative frequency dependent) selection".  In well-mixed infinite populations, a non-zero balancing 
selection is sufficient to maintain polymorphism and biodiversity. Here we show that the behavior is 
different when the population is embedded in low-dimensional spaces. In particular, in one dimension 
polymorphism needs a critical threshold of balancing selection, below which the population undergoes 
genetic demixing and eventually fixation. 

<p style="font-size:smaller;">This is joint work with L. Dall'Asta (Dipartimento di Fisica and Centre for Computational Sciences 
- Politecnico di Torino) and D. Begh&eacute; (Dipartimento di Biologia Evolutiva e Funzionale,
Universita degli Studi di Parma)</p>