GENETICS AND HEREDITY AN INTRODUCTION TO BIOLOGY

WHAT IS GENETICS? Genetics is the study of characteristics and genes that are passed down from parents to their offspring. We can examine characteristics such as: hair color, eye color, thumb type, and earlobe type

FATHER OF GENETICS-GREGOR MENDEL Known as the discoverer of the gene and the father of genetics. In his spare time, he bred pea plants and made hybrid plants. He would try to mix plants to get specific traits— such as height, texture of the plants. He first discovered that when tall plants crossed with short ones, they produced tall ones rather than medium ones. He was able to determine that some genes were dominant and some were recessive.

GREGOR MENDEL PEA PLANT EXPERIMENT When Mendel bred one tall plant and one short plant, 2 tall plants were created. When those two tall plants were bred together, he got 3 tall plants and one short plant. This illustrated to him that there were dominant genes and recessive genes.

DOMINANT AND RECESSIVE GENES Dominant - a gene in one strand of DNA that is stronger than the corresponding gene in another strand of DNA. Recessive - a gene in one strand of DNA that is weaker than the corresponding gene in another strand of DNA. Brown eyes are dominant genes.Blue eyes are recessive genes.

ACQUIRED VS. INHERITED TRAITS Inherited traits are traits that you are born with and cannot change—such as your height, or the color of your hair and eyes. However, you can change the appearance of your inherited traits and acquire new traits. To make yourself look taller, you could wear high heels. To change your eye color, you could wear colored contact lenses. These changes would be temporary and would not change your inherited traits permanently.

PUNNETT SQUARES Punnett Squares can help figure out the odds of two parents passing on particular genes to their children. This example shows how hair color genes could be passed down from mother and father to their children. This particular offspring has a higher likelihood of having black hair.