 Genetics is the overall study of genes and heredity. Kind of like how Biology is the study of living things.

1. Heredity: The passing of traits from parents to offspring (children) 2. Trait: A physcial characteristic that describes an organism ex. Height or eye color 3. Gene: A section of DNA the determines a trait 4. Allele: One of the different forms of a gene ex. Tall allele or short allele

 Trait - any characteristic that can be passed from parent to offspring  Each trait can be is controlled by at least two genes. Traits can be dominant or recessive depending upon the genes that make them up.

 Dominant Traits-The strongest trait, this trait is always visible if there is at least one dominant gene.  Recessive Trait-The weakest trait, this trait is often not visible. For a recessive trait to show up it has to be expressed by two recessive genes.

 The following is a list of genetically inherited traits you get from your parents.  Color Blindness  Cystic Fibrosis  Down Syndrome  Hemophillia  Sickle Cell Disease  Some forms of Cancer  Being Bald  Attached or free-hanging earlobes  Widows peak  Hitchhikers thumb

 all characteristics that organisms have are inherited from their parents but some can be influenced by environmental factors.

 Are traits that your parents give you.  They distinguish one organism from another  Some inherited traits are dominant, some are recessive, and some are neither.  Examples: color of flowers, shape of leaves, eye color, blood type, skin color…..

 Straight pinkies  Attached earlobes  Cleft chin  Hitchhikers thumb  Widows peak  Hair that goes clockwise

 Acquired traits are traits that occur after an organism is born. Acquired traits can be caused by environmental factors such as temperature, nutrients, injuries, disease, exposure to sun, or living conditions. Physical characteristics of organisms may be influenced by environmental factors.

1. Temperature, may affect the number or size of leaves in plants or the color or amount of fur or thickness of skin in animals. 2. Nutrients, may affect the growth or seed production in plants or the weight or height in animals. 3. Injuries, may cause scarring in plants and animals. 4. Disease, may affect the number of branches in plants or body shape in animals

 5. Exposure to sun, may affect the color of leaves in plants or skin changes in animals.  6. Living conditions, may affect the leaves, roots, and height in plants, or the condition of fur, skin, or teeth in animals.

 Gregor Mendel is known as the father of Heredity. He was an eastern European monk and studied pea plants.  Gregor Mendel was born in 1822 in the Czech Republic.

 Mendel found that certain characteristics of pea plants were passed on from the parent plants to the offspring. These characteristics or genetic traits were caused by factors called genes.

 Site of Gregor Mendel’s experimental garden in the Czech Republic

 com/watch?v=GTiOE TaZg4w com/watch?v=GTiOE TaZg4w

 A gene is a stretch of DNA whose sequence determines the structure and function of a specific functional molecule (usually a protein)  Genes are located in the cell nucleus on chromosomes

 We use the letters of the alphabet as gene symbols to represent genes.  Every characteristics is caused by at least two genes.  Gene symbols are chosen by using the first letter of the strongest or dominant trait for both genes. For example if the dominant trait for a flower as to be yellow the gene symbol would be Y.

 A capital letter is used for the strong trait (gene) and a lower cased letter is used for the weak trait.  A strong trait is called dominant and a weak one is called recessive.

 Whenever a dominant gene is present, it shows itself, but it takes two recessive genes (together) to show themselves.  When two genes are exactly the same for a trait, they are called purebred. When they are not the same they are called hybrid.

 The phenotype refers to the visible expression of the genes, or what can be seen with the naked eye.  The genotype is the actual gene make-up of the organism.

 Alleles are the different forms of genes. Two alleles for each gene are inherited, one from each parent.  Homozygous-2 dominate or 2 recessive alleles  Heterozygous-one dominate and one recessive allele

 Incomplete dominance or co-dominance is a rare instance when no gene dominates and a mixture of the two traits shows up as the trait of the offspring. For instance, in roses, a red rose crossed with a white rose produces a pink rose.

 We often times use Punnett Squares to organize all the possible combinations of offspring from particular parents.

 One cat carries heterrozygous, long-haired traits (Ss), and its mate carries homozygous short-haired traits (ss). Use a Punnett Square to determine the probability of one of their offspring having long hair.  What is the probability that their offspring will have short hair.

 PBS Video PBS Video  1. Instructions for a Human Being.  3. One Wrong Letter