After a WGD, one of the duplicated gene pair is often lost through fractionation; less than 10% of WGD gene pairs have remained in S. cerevisiae genome.  A little over half of WGD gene pairs in the glycolysis reaction pathway were retained in post-WGD species, significantly higher than the overall retention rate.  This has been associated with an increased ability to metabolize glucose into pyruvate, or higher rate of glycolysis.  After glycolysis, pyruvate can either be further broken down by pyruvate decarboxylase (Pdc) or pyruvate dehydrogenase (Pdh).  The kinetics of the enzymes are such that when pyruvate concentrations are high, due to a high rate of glycolysis, there is increased flux through Pdc and thus the fermentation pathway.  The WGD is believed to have played a beneficial role in the evolution of the Crabtree effect in post-WGD species partially due to this increase in copy number of glycolysis genes.