Here, the authors map this colour polymorphism to a putative regulatory region for follistatin on the Z chromosome and suggest it is maintained by balancing selection.
The present study provides further support to the view that evolution of dominance may be an efficient mechanism to remove unfit heterozygotes that are maintained by balancing selection.
Strains of A. flavus that do not produce aflatoxin (nontoxigenic strains) are fairly common in nature, strongly suggesting that this polymorphism is maintained by balancing selection, i.e., that aflatoxin production may be favored in some environments but selected against in others.
The advantageous mutations approach to genetic fixation under directional selection; the advantageous heterozygotes are maintained by balancing selection; and purifying selection removes the deleterious mutants.
Presumably, the variants maintained by balancing selection may be associated additional intermediate phenotypes other than polydactyly.
Resting calcium levels were maintained by balancing extrusion with a nonspecific leak current associated with each calcium extruder.
It has therefore been proposed that the high diversity at the MHC is maintained by balancing selection, caused by coevolution between hosts and pathogens.
In contrast, analysis of patterns of nucleotide substitutions provided evidence that polymorphisms in the ama1 gene of both species are maintained by balancing selection, particularly in domain I.
In these cases, introns are likely maintained by balancing the selective forces favoring their maintenance with other mutational and/or selective forces acting on genome size.
This additional level of variation may be maintained by balancing selection, thereby maximizing the coding potential of the Mup genes two-fold within any individual and permitting even single Mup genes to provide limited species-specific information.
A unique feature of the human KIR system, and one not mirrored in other higher primates, is the segregation of two distinctive groups of haplotypes (A and B) [23], which are present in all the >150 human populations examined and are maintained by balancing selection [24].
