The favoring of both versions together is called a balancing selection.

There are several ways balancing selection works to maintain polymorphism.

This balancing selection can keep two versions of a gene around in a population indefinitely.

The mechanisms that conserve it are types of balancing selection.

Evidence is now strong that many polymorphisms are maintained in human populations by balancing selection.

This is an example of balancing selection.

This is consistent with a heterozygous or balancing selection coefficient for these loci.

It is a type of balancing selection.

Similar arguments apply when variation is a pleiotropic side-effect of balancing selection.

In molecular evolution, he emphasized the importance of advantageous mutations and balancing selection.

The continued presence of the O alleles is hypothesized to be the result of balancing selection.

Known to Szondi as heterosis, it is currently known as "balancing selection."

Also, some highly variable segments are thought to be caused by balancing selection, but there are also studies against this hypothesis.

The sickle cell trait is thus an example of heterozygote advantage which is subject to balancing selection.

Evidence for balancing selection can be found in the number of alleles in a population which are maintained above mutation rate frequencies.

"Signature of balancing selection in Arabidopsis".

There are several mechanisms (which are not exclusive within any given population) by which balancing selection works to maintain polymorphism.

"Balancing claims for balancing selection".

Lewontin and Hubby's paper also discussed the possible explanation of the high levels of variability by either balancing selection or neutral mutation.

These two conflicting forces (homogenization and polymorphism) suggest that a balancing selection for trichromacy is present in the form of heterozygote advantage.

Finally, a number of forms of balancing selection exist, which do not result in fixation, but maintain an allele at intermediate frequencies in a population.

If such balancing selection maintains a substantial fraction of life-history variation, it will generate negative genetic correlations among life-history traits.

Finally, balancing selection can occur through frequency-dependent selection, where the fitness of one particular phenotype depends on the distribution of other phenotypes in the population.

In heterozygote advantage, or heterotic balancing selection, an individual who is heterozygous at a particular gene locus has a greater fitness than a homozygous individual.

A positive Tajima's D signifies low levels of both low and high frequency polymorphisms, indicating a decrease in population size and/or balancing selection.