The authors of the D614G paper do attempt to rule out a founder effect. I'm not saying their analysis is bullet proof, but the OP doesn't address its merits. T

The authors of the D614G paper do attempt to rule out a founder effect. I'm not saying their analysis is bullet proof, but the OP doesn't address its merits. To differentiate between founder effects and a selective advantage driving the increasing frequency of the G clade in the GISAID data, we applied the suite of tools that we had been developing for the SARS-CoV-2 analysis pipeline (Fig. 2, Fig. 3, Fig. S2 and Fig. S3). A clear and consistent pattern was observed in almost every place where adequate sampling was available. In most countries and states where the COVID-19 epidemic was initiated and where sequences were sampled prior to March 1, the D614 form was the dominant local form early in the epidemic (orange in Figs. 2 and 3). Wherever G614 entered a population, a rapid rise in its frequency followed, and in many cases G614 became the dominant local form in a matter of only a few weeks (Fig. 3 and S3).