Fig. 4.

Although the fraction of MDA families with a particular number of members has a power-law dependence on the family size (as shown by the linear log–log plots), the fraction of SDA families with a particular number of members does not. For MDA families, the fraction of families with m members varies as m^−2.09. For small SDA families, the fraction drops much more slowly than that for large SDA families (varies as m^−0.18 for m < 32 and then as m^−2.57 for m > 64).