Molecular evolution studies the mechanisms leading to present day deoxyribonucleic acid and protein sequences – it is a unifying force in biology. With the advent of the genomic era, it is expected to continue reducing the gap between molecular biology and the ecology of organisms. Some of the key advances are quantitative estimates of both the diversity in populations and of evolutionary relationships, as well as improvements in theoretical understanding. There is an improved understanding of the function of proteins and much better models of the common patterns of development. There are now powerful models for the origin of life, and at the other end of the scale, an important aspect has been the detailed models of the origin and distribution of modern humans.

Key Concepts:

• Studies in Molecular Evolution developed very quickly once protein sequence (and then DNA sequence) information became available.
  
• Molecular data inform every aspect of evolution, and similarly, molecular biology needs molecular evolution to understand it.
  
• Evolutionary trees from molecular data have been, and continue to be, a major application of DNA sequences.
  
• The neutral theory of evolution was an important early contribution, implying on-going mutations occurred irrespective of any ‘need’ of the organism.
  
• Gene duplication, and then divergence of the two copies, is an important source for the origin of New Information.
  
• The origin of life can now be studied scientifically, and its main contribution is a proposed RNA-world where RNA is involved in both information storage and catalysis.
  
• Nothing in macroevolution has been found thus far that is not explained by normal microevolutionary molecular processes.
  
• Molecular evolution shows a basic similarity of all living cells, reinforcing the common unity of all life on earth.
  
• There are excellent data supporting an African origin of modern humans and spreading from there around the world (with a little introgression from earlier groups).