Animal Science Department


Date of this Version



Presented at Range Beef Cow Symposium XXII, November 29, 30, and December 1, 2011, Mitchell, Nebraska. Sponsored by Cooperative Extension Services and the Animal Science Departments of the University of Wyoming, Colorado State University, South Dakota State University, and the University of Nebraska–Lincoln.



I am continually amazed at the tools we have in today’s world to assist in making better and better decisions. This is true in most aspects of our lives – from communications to computers; from entertainment to eating; from politics to travel; and many, many more components of what we do and how we live. The digital age has created an information explosion, and livestock production has not been left out of this progress.

Another amazing aspect of today’s world is the vast knowledge being uncovered and refined in the world of biology and science. Gregor Mendel, an Austrian friar, now known as the "father of modern genetics", studied variation in plants in 1830. Mendel’s work later lead to Mendel's Laws of Inheritance which are key components of modern genetic predictions today. Deoxyribonucleic acid or DNA was first isolated by the Swiss physician Friedrich Miescher who, in 1869, discovered a microscopic substance in the pus of discarded surgical bandages that later was characterized and determined to be integral to the mechanisms of inheritance. James D. Watson and Francis Crick proposed the double helix or spiral staircase structure of the DNA molecule in 1953. This led to their being awarded a Nobel Prize in 1962. Today, information from DNA is used widely in forensic investigations, genetic counseling in humans, study of disease susceptibility, and in genetic merit of cattle.

DNA as an Information Source

DNA is the genetic material of most living organisms, and is the major constituent of chromosomes within the cell nucleus of all cells. DNA plays a central role in the determination of inheritance characteristics in organisms by controlling protein synthesis in cells. DNA is a specific type of a chemical molecule called nucleic acid and is composed of two chains called nucleotides in which the sugar called deoxyribose makes up the backbone chain and four chemical bases (adenine, cytosine, guanine, and thymine) provide cross bars between the backbone chains. The two chains are wound round each other and linked together by hydrogen bonds between specific complementary bases to form a spiral ladder-shaped molecule.

The sequence of bases in DNA forms the genetic code. A group of three bases (a triplet) is the key signal for the production of a particular amino acid in the cytoplasm of the cell. A sequence of triplets in the DNA molecule may code for a complete protein. The different amino acids, and the order in which they are joined up, determine the protein being produced. The sequence of the triplets forms a gene. There may be thousands of base pairs in any one gene.