Decreased Genetic Drift under the Overlapping Conservation

In order to understand the genetic drift under closed population using equaled family size, two overlapping conservation methods proposed (increment and decrement) were introduced to compare with the discrete population. Finally, the article showed body weight controlled by hundred loci having average gene effect. For increment, the second generation had the parents composed of 400 original population and 100 from first generation; the third population consisted of 300 original population, 100 from first generation and 100 from second generation. The fourth population was composed 200 from original population, 100 from first population, 100 from second population, 100 from third population, and 100 from the fourth population. The fifth population was achieved by randomly selecting 100 from each population. For decrement, the method has the opposite direction. For different population, both more than one thousand and less than family sizes 10 have the stable gene frequency despite the different initial gene frequency and sex ratio. Despite several generations were maintained together, less than 5 generations increment conservation can make the gene frequency improved to less than 0.5, while more than 0.5, increment conservation can make them decrease to less than 5 generations and reach the stable higher gene frequency in the following generations. Generally, less than 0.4 gene frequency can use in the increment conservation. More than 0.7, you can use the decrement method. When 100 loci which have average gene effect and random initial gene frequency were assumed, both increment and decrement conservation methods can keep the phenotype stable.