English

Computer Modeling of Genome Evolution during Sympatric Speciation

By  





In the natural, even large and panmictic populations, the inbreeding coefficient could be relatively high, because individuals are looking for sexual partners in the relatively short distances. We have simulated the evolution of such population on the square lattice. Results of simulations were compared to the human population and its genetic pool. In particular, we have analyzed distribution of recombination spots along the human chromosomes using the method of cumulative detrended walks. Frequency of recombination in all human chromosomes (excluding chromosome Y which has no partner for recombination) is higher in the subtelomeric regions (both ends of chromosomes) and relatively lower in the middle part of chromosomes. This resembles the distribution of accepted recombination events in the bitstring representing haplotypes in the computer simulated populations. In our simulations, individuals before reproduction have to produce gametes connected with some probability of recombination between haplotypes (bitstrings). We consider that recombination event is accepted if gamete produced by this recombination succeeded in forming the surviving zygote. Under high inbreeding and low frequency of intragenomic recombinations the middle parts of bitstrings in one genome complemented each other while at the ends the defective alleles are eliminated by purifying Darwinian selection. Such conditions are characteristic for populations after sympatric speciation. In conclusion, the middle part of chromosomes is more conserved and its structure seems to be responsible for belonging to higher taxons, while at the ends of chromosomes genes responsible for the intra species biodiversity are located.
Find OpenCourseWare Online Exams!
Attribution: The Open Education Consortium
http://www.ocwconsortium.org/courses/view/d4c0cc3c1e41c3789695fdd840d3aa53/
Course Home http://videolectures.net/eccs07_cebrat_cmg/