Genetics For Dummies, 3rd Edition

Chapter 3

Visualize Peas: Discovering the Laws of Inheritance

IN THIS CHAPTER

Appreciating the work of Gregor Mendel

Understanding inheritance, dominance, and segregation of alleles

Solving basic genetics problems using probability

All the physical traits of any living thing originate in that organism’s genes. Look at the leaves of a tree or the color of your own eyes. How tall are you? What color is your dog’s or cat’s fur? Can you curl or fold your tongue? Got hair on the backs of your fingers? All that and much more came from genes passed down from parent to offspring. Even if you don’t know much about how genes work or even what genes actually are, you’ve probably already thought about how physical traits can be inherited. Just think of the first thing most people say when they see a newborn baby: Who does he or she look most like, mommy or daddy?

The laws of inheritance — how traits are transmitted from one generation to the next — were discovered less than 200 years ago. In the early 1850s, Gregor Mendel, an Austrian monk with a love of gardening, looked at the physical world around him and, by simply growing peas, categorized the patterns of genetic inheritance that are ...