Sympatric speciation

Background

In the model of evolution on lattice like in nature at the edges of the expanding populations inbreeding is higher than inside (pioneers live in small groups) which increases the possibility of meeting two identical haplotypes or chromosomes in one zygote (like two bitstrings 10001, 10001). This promotes the strategy of looking for complementary haplotypes (like bitstrings 10001 and 01110). In complementary pairs of haplotypes they fit each other producing heterozygous loci. Nevertheless, this strategy produces specific sequences of defective alleles in haplotypes. Independently evolving groups of organism, under the regime of high inbreeding may produce different configurations of these defects in the evolving haplotypes. Such groups of organisms may emerge as new species with no possibility of generation surviving hybrid offspring. We have tested such an evolution in our model.

Computer model

• individuals occupy square lattice of size 1000 x 1000.
• each pixel corresponds to one individual
• colour is directly determined by haplotypes of individual, so different colours mark different genome
• for every female, male is taken at distance <=D, and child is placed at distance <=d
• recombination occurs with probability P=0..1
• there is one mutation per generation

All of the following pictures are snaphots taken of populations with different starting conditions at 1100th generation.

Available resources: