Skip to main content
. 2006 Sep;16(9):1119–1125. doi: 10.1101/gr.5318106

Figure 4.

Figure 4.

Model of the evolutionary histories of chrIa and chrIb. (A) Original A&E cross. (A) blue; (E) pink; (shorter bar) chrIa; (longer bar) chrIb. (B) Recombinant progeny from a restricted gene pool. A special chrIa (black outline), generated by recombination, carries allele(s) that allow or enhance transmission between intermediate hosts, permitting asexual propagation and suppressing recombination events that might break up the special combination of alleles. (C) Asexual growth expands the lineage in the population. Infrequent sexual events with highly recombinant relatives from the original cross allow parasites with the special chromosome Ia to acquire highly recombinant chromosomes including chromosome Ib. These new recombinant parasites can now expand in the population through asexual growth. (D) Natural selection for asexual growth maintains the special chrIa intact and three different clonal lineages (i.e., Types I, II, and III) expand and become predominant in the population.