Mammalian Molecular Clock

This study explores the rate of molecular evolution in mammals.

Various methods of comparative analysis have been applied to different kinds of molecular data in attempts to resolve the issue.

The choice of molecular data, and more importantly, the different assumptions made in the analysis, have resulted in contrasting conclusions being drawn.

These assumptions are critically evaluated and the conclusion is drawn that, for "silent" DNA, the molecular clock hypothesis cannot be rejected.

For amino acids, the clock hypothesis is rejected, and this appears to reflect the action of natural selection.

The implications of the DNA clock in relation to the pattern of mammalian evolution and the process of mutation are discussed.