This is a very basic population genetic simulation. Here, rather than being concerned with individual histories, we are concerned with the overall frequency of different alleles (genetic variants) in a population.
Each red point represents the frequency of a 'good' allele (fitness equals 1.0), while each gray point represents the frequency of a 'bad' allele (fitness equals 0.0). Over time these frequencies change due to the combined actions of genetic drift, mutational pressure and selection. Past frequencies can be seen as a trace extending backwards in time.
With a large population (UP) or a high rate of mutation (RIGHT) there will be abundant variation, while with a small population (DOWN) or a low rate of mutation (LEFT) there will usually only be a single allele at any given moment. A single mutation moves only one step up or one step down (or left and right if 2D is activated), creating correlation between the frequencies of adjacent alleles.
Additionally, each allele is shaded based upon its long-run frequency. Lighter shades for more successful alleles and darker shades for less successful variants.
Press H to bring up a listing of commands. Running this in the browser is significantly slower than running it as its own application. Also, fonts are kind of broken by the browser for some reason. You can download executables and source code if you'd like.
Posted March 11, 2010