Chapter 2 Your Heredity

 Chromosomes  Where heredity information is stored  Gene  The basic unit of heredity  Dominant gene  The more influential gene  Recessive Gene  The less influential gene Vocabulary

 Mutations  Chemical changes in genes  Fraternal Twins  The product of 2 eggs fertilized by one sperm  Identical Twins  The product of 1 egg fertilized and the egg divides Vocabulary

 Autosomes  The 22 chromosomes that both male and female have  Sex Chromosomes  The chromosomes of the 23 rd pair that determine baby’s sex  Blood type  This is the type of blood you have. Blood types are divided into 4 main types  Rh factor  A specific blood element. This is a problem if mother is RH negative and father is RH positive. Vocabulary

 Where is information about your heredity stored?  What is the basic unit of heredity?  What are dominant and recessive genes?  How do mutations occur? The Process of Heredity

 Mirror imaging  Characteristics appear on opposite sides of body  Conjoined twins  Twins that are born physically linked  Once a mother has had twins her chances of having twins are times greater Twins

 A female carries two X chromosomes  A male carries an X and Y chromosome  There are other characteristics determined by the sex chromosomes  These are called sex-linked characteristics  Color blindness  Hemophilia Sex Chromosomes

 There are 4 different blood groups  A B AB and O  A person’s blood type is determined by genes  42% of people in the US have type O  Type O is universal  8% of the population have AB  RH factor can be a c0mplication during pregnancy if the,mother is RH – and father is RH + Blood Types

 Life expectancy is genetic and environmental  Average life span of American colonists was 35  Now the average life span is more than 70 years  There is a tendency for women to live longer  More males are born but more boys than girls die during childhood Longevity

 Look at the chart on page 55. What are some of the Dominant and Recessive traits you have inherited? Physical Characteristics

 Some diseases and defects are genetic.  Sometimes you can have the genes for a disease but you will not have the disease  Environment plays a role in disease and defects Diseases and Defects