Gregor Mendel ( ) Augustinian monk who taught natural science to High school students. He was born in Moravia, Czech Republic Mendel was a brilliant youngster but his family was very poor!! So, he entered an Augustinian monastery to continue his education and start his teaching career.

Planting the Seeds of Genetics Between 1856 and 1863 Mendel patiently cultivated and tested at least 28,000 pea plants Between 1856 and 1863 Mendel patiently cultivated and tested at least 28,000 pea plants He studied and analyzed the shape of seed, color of seed, tall stemmed and short stemmed, and tall plants and short plants He studied and analyzed the shape of seed, color of seed, tall stemmed and short stemmed, and tall plants and short plants All of these are called : Traits All of these are called : Traits

Gregor Mendel Came up with the basic laws of Came up with the basic laws of Heredity Heredity Mendel ' s work became the Mendel ' s work became the foundation for modern Genetics. foundation for modern Genetics. Many diseases are known to be inherited Many diseases are known to be inherited He found actual proof of the existence of Genes He found actual proof of the existence of Genes At that time no one knew what genes were At that time no one knew what genes were

Traits What is a Trait? A physical, visible characteristic Example: Pea shape, pea color……. Dominant : trait shows up in an offspring (You can actually see it) Recessive t t t trait is masked by dominant trait (You can’t see the recessive trait, but it is present in the organisms)

Heredity and Genetics What is Heredity ? What is Heredity ? The passing of traits The passing of traits from parents to their from parents to their offspring or children offspring or children What is Genetics ? What is Genetics ? The Scientific study of Heredity The Scientific study of Heredity Gregor Mendel is known as……… ? Gregor Mendel is known as……… ? The Father of Genetics

- Mendel’s Work Mendel ’ s Experiments In all of Mendel’s crosses, only one form of the trait appeared in the F1 generation. However, in the F2 generation, the “lost” form of the trait always reappeared in about one fourth of the plants. P Generation F 1 Generation F 2 Generation

Mendel ’ s Pea pod experiment Mendel ’ s Pea pod experiment F i r s t G e n e r a t i o n o r F 1 : A l l o f t h e o f f s p r i n g w e r e y e l l o w ! W h a t a s u r p r i s e f o r M e n d e l ! W h e r e a r e t h e g gg g r e e n p e a s ? ? ? ? Second Generation or F 2 : 3 offspring were yellow 1 offspring was green P a r e n t P e a s

What is a Gene? A factor that controls a specific trait Example: Gene for hair color, eye color, pea color…. Is gene a piece or segment of DNA? Yes it is!! So, what is an Allele? Different form of a gene Example: Allele for hair color can be: Black hair, Brown hair or Blonde hair Genes and Alleles

Dominant and Recessive Alleles Dominant and Recessive Alleles What is an Allele? * A trait controlled by a specific gene: Example: Hair color Eye color Height Body shape Each trait has 2 alleles: 1. One allele from the Mother 2. Second allele from the Father

Dominant and Recessive Alleles Dominant allele Dominant allele * The allele you can see * The allele you can see * Covers up or masks the * Covers up or masks the recessive allele recessive allele Recessive allele Recessive allele * Only shows if dominant allele * Only shows if dominant allele is not present is not present * Both alleles have to be recessive * Both alleles have to be recessive

1. How many traits did Mendel Study? Seven 2. What is the Recessive allele for Pod Color? Yellow 3. Is the yellow seed controlled by dominant or recessive allele? Dominant 4. For all of the alleles, which color is recessive? Yellow 5. Which seed shape is Dominant Round Genetics of Pea Plants Genetics of Pea Plants

Mendel ’ s Crosses What is a Purebred plant? * Plant (or any organism) that produces same form of trait as the parent * Both alleles are either: a. Dominant – Tall plant b. Recessive - short plant What is a Hybrid Plant? * Plant that has one dominant and one recessive allele for a trait

Using Symbols in Genetics To represent or show alleles what do scientists use? Answer: They use letters What type of letters are used to show a Dominant allele? Answer: Uppercase letters TT BB MM What type of letters are used to show a recessive allele A Answer: Lower case letters aa mm tt

Mendel ’ s Pea pod experiment

Yellow Pea = Dominant Yellow Pea = Dominant Green Pea = Recessive Green Pea = Recessive First Generation or F 1: First Generation or F 1: All peas are Yellow or All peas are Yellow or Dominant Trait Dominant Trait Second Generation or F 2: Second Generation or F 2: Three peas are yellow Three peas are yellow one pea is green one pea is green Ratio is 3:1 Ratio is 3:1

First generation of F1 and Second generation orF2

First Generation or F 1: What are the colors of the parents in the First generation? Answer: One parent is white the other purple W Which color is Dominant in the offspring? Answer : Purple flower “Ww” is Dominant

First Generation or F 1: Which color is recessive? Answer: White flower “ww” is Recessive So, in F1 generation what color are all of the offspring? Answer: All 4 offspring are Dominant Purple “Ww”

Second Generation or F 2: What color are the parents in the Second Generation or F2? Answer: Both parents are Purple – Ww Why are the parents purple even when they have the white allele? Answer: Because the purple color allele is Dominant/covers up the recessive white c c c color allele

Second Generation or F 2 How many offspring are Purple? Answer: Three offspring are Purple Ww What color is the 4th offspring? Answer: The offspring is white W What is the ratio of colors in the Second Generation? Answer: The ratio in the second generation is 3 purple : 1 white 3 3 : 1

Mendel ’ s Recognition In 1900 Mendel ' s work was finally recognized by three independent investigators. In 1900 Mendel ' s work was finally recognized by three independent investigators. One of these being the Dutch botanist, One of these being the Dutch botanist, Hugo De Vries. Hugo De Vries. But it was still not until the early 1920 s and early 1930 s that the full significance of his work was recognized particularly how it related to Evolution of organisms But it was still not until the early 1920 s and early 1930 s that the full significance of his work was recognized particularly how it related to Evolution of organisms

Review questions 1. Where was Gregor Mendel born? Answer: In Czech Republic 2. How many pea plants did he study? Answer: Around 28, What is an allele? Answer: A trait controlled by a specific gene 4. What is a dominant allele? Answer: An allele or trait that always shows up if it is present in the organism 5. What is a recessive allele? Answer: An allele or trait that is masked by the dominant allele (Can’t see the trait)

6. Why do we have 2 alleles for the same trait? Answer: One from mom and one from dad 7. What letter combinations can you use to show a dominant trait? A recessive trait? Answer: Dominant: BB or Bb Recessive: bb 8. What did Gregor Mendel study? Answer: Pea Plants 9. How many traits in peas did Mendel study? Answer: Seven 10. What is Gregor Mendel called? Answer: The Father of Genetics

Using Symbols in Genetics Dominant Allele : Dominant Allele : a. Represented by a Capital letter a. Represented by a Capital letter b. Brown or “ B ” eye color is dominant over b. Brown or “ B ” eye color is dominant over blue or “ b ” eye color blue or “ b ” eye color Recessive Allele : Recessive Allele : a. Represented by lower case letter a. Represented by lower case letter b. Blue or “ b ” eye color is recessive or masked by Brown or “ B ” eye color b. Blue or “ b ” eye color is recessive or masked by Brown or “ B ” eye color Brown eyes can have these allele combinations Brown eyes can have these allele combinations BB or Bb BB or Bb only have this combination Blue eyes can only have this combination bb bb