Friday, June 13, 2008

Population Genetics

Population Genetics has been used as a tool for figuring out how genes express themselves in populations. The Britons R.A. Fisher and J.B.S. Haldane and the American Sewall Wright founded this discipline and others have added to it. It is part of a model called the Modern Evolutionary Synthesis. Many evolutionary scientists, including Richard Dawkins, are relying on its principles to explain evolution.

The model explains genes within breeding populations using observation, graphs for data and mathematics. It uses genetic material that already exists to examine the variation that can take place in a species. For example, a moth can change color over a period of time if the change helps to protect it from predators. The population geneticists can look at the genes for color and track how they change.

The main premise was worked out before structures in DNA and proteins were discovered. The Synthesis scientists have incorporated new genetic information into their theories. They have been successful in applying mathematics to some biological phenomena. However, they have had problems in giving the details of how evolution has worked in the large jumps it has supposedly made at certain times. These large jumps include the origin of life, the development from what is called a prokaryotic cell (e.g. bacteria) to a eukaryotic cell (literally a true cell), and multicellular, multisystem animals. In these large jumps, new genetic material is needed, not just pre-existing DNA. ID advocates ask when and how the new material was generated.

So, some people look at proteins and their amino acid and DNA sequences and see material which can be used in other ways for proteins so that they can evolve into other structures. These generally are the Population Genetics crowd. Others look at the sequences and want to know how exactly such complex structures could have gotten to the point they are at. The ID advocates belong to the latter group, because when they apply the numbers to probabilities for new genetic information, they see probabilities that are minute in the extreme. The improbability is not the only factor, however. It is the fact that these improbable products are also functional. That is known as specified complexity.

This is a difference in perspective that should be kept in mind when evaluating what scientists tell us about evolution.

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The book Creation and Evolution, compiled by Stephen Horn and Siefgried Wiedenhofer (Ignatius Press, 2008), became available May 28. I hope to give you a review next week. The book is about a group that has met with Pope Benedict XVI for many years. They are former students of his at the Universities of Bonn, M√ľnster and meet with him annually in summer to discuss theology and related issues. They sometimes have invited guest speakers. This book is the first to give a summary of their meetings, and covers their speeches and discussions about creation and evolution.

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