A markedly positive Tajima's D value, as observed at the NAT2 gene, is expected under balancing selection [35], [36], which can act in the form of heterozygote advantage, frequency-dependent selection or changes in the selective regime over time and/or space.
The major mechanisms for balancing selection are heterozygote advantage, frequency-dependent selection, or environmental heterogeneity.
This is called balancing selection and it reflects the situation where alleles are retained in a population by forms of selection such as heterozygote advantage, frequency-dependent selection [ 37] or selection varying in space and time that favours some alleles in certain environments [ 38].
These include the following: gene pools, allele frequencies, Hardy Weinberg equilibrium, genetic bottlenecks, genetic drift, gene flow, relative fitness, good genes theory, heterozygote advantage, frequency-dependent selection, neutral genetic variation, polyploidy, hybrid zones, speciation, self-replicating RNA, and evolutionary aspects of development.
However, both associations utilising these 21 events (selective advantage-relative hazard and selective advantage-frequency of CTL targeting) were significant (P = 0.008, P = 0.017) and the latter is also predicted by classical population genetics theory.
We also found a slight advantage for frequency terms in regard to intraindividual stability, adding further evidence to the assumption that frequency scales might be easier to use for patients than intensity scales.
Reversely, pre-stack data have also been used (e.g., Dasgupta and Clark 1998), because the pre-stack data have an advantage in frequency preservation.
Moreover, in order to take advantage of frequency diversity, subcarrier interleaving is applied to the 9 subcarriers belonging to the same OFDMA user segment.
On the other hand, pre-stack data have a disadvantage in S/N ratio, and reversely it has an advantage in frequency preservation.
At this point, two questions arise: how this correlation factor affects the multicast throughput and how we can take advantage of frequency diversity with as little as possible degradation in the achievable multicast rate.
