1. Heredity It’s all in the genes

2. Why do I look like my Dad (or Mom)? My mom and dad My brother and I

3. Why does my daughter look like me (and my wife)?

4. The answer……

5. What is heredity? Heredity is the passing of traits from parent to offspring Heredity is the passing of traits from parent to offspring You inherit traits from your biological parents You inherit traits from your biological parents Both of your parents are responsible for passing on your traits to you Both of your parents are responsible for passing on your traits to you

6. What are traits? Characteristics that are passed on from parents to offspring Characteristics that are passed on from parents to offspring Eye Color Hair Color Body Structure Facial Features Skin Color

7. So Who Figured all this out? Gregor Mendel Gregor Mendel Austrian monk Austrian monk Worked at the monastery in the garden Worked at the monastery in the garden Noticed that there were patterns in the ways that the peas reproduced Noticed that there were patterns in the ways that the peas reproduced Noticed that some parent plants looked like the offspring and other did not Noticed that some parent plants looked like the offspring and other did not He wanted to know why!!! He wanted to know why!!!

8. Mendel chose pea plant for several reasons They reproduce sexually They reproduce sexually They have two distinct, male and female, sex cells called gametes They have two distinct, male and female, sex cells called gametes Their traits are easy to isolate Their traits are easy to isolate Generation time was short Generation time was short

9. Carrying out the crosses Designed a set of experiments to test his ideas Designed a set of experiments to test his ideas Monohybrid crosses (involve a single trait) Monohybrid crosses (involve a single trait) Cut off the anthers of one flower and used the pollen from these anthers to fertilize the stamen on another plant. Cut off the anthers of one flower and used the pollen from these anthers to fertilize the stamen on another plant. Used the pollen from a plant with one trait to fertilize the plant with the opposite trait (purple flowers vs. white flowers) Used the pollen from a plant with one trait to fertilize the plant with the opposite trait (purple flowers vs. white flowers) The stigma of the flower actually turns into seeds (peas). These seeds/peas are then planted in the ground to produce more pea plants. The stigma of the flower actually turns into seeds (peas). These seeds/peas are then planted in the ground to produce more pea plants. Observed the first generation (F1) offspring Observed the first generation (F1) offspring

10. Mendel’s Pea Plants Noticed that some patterns of inheritance made sense and other did not. Noticed that some patterns of inheritance made sense and other did not. Crossed purple and white-  all of the offspring had purple flowers ???? Crossed purple and white-  all of the offspring had purple flowers ???? Crossed purple offspring with each other -> ¼ offspring had white flowers Crossed purple offspring with each other -> ¼ offspring had white flowers Mendel wanted to know why????? Mendel wanted to know why?????

11. Mendel’s Pea Plants 7 traits of pea plants. 7 traits of pea plants. Crossed plants with two different forms of each trait (for example, smooth/wrinkled peas or yellow/green peas) to determine which traits would appear and how often. Crossed plants with two different forms of each trait (for example, smooth/wrinkled peas or yellow/green peas) to determine which traits would appear and how often. Determined which of the 7 traits were dominant and which were recessive. Determined which of the 7 traits were dominant and which were recessive.

12. What did Mendel discover? The Rule of Unit Factors The Rule of Unit Factors Each organism has two alleles for each trait Each organism has two alleles for each trait Alleles - different forms of the same gene Alleles - different forms of the same gene Genes - located on chromosomes, they control how an organism develops Genes - located on chromosomes, they control how an organism develops

13. What did Mendel Discover The Rule of Dominance The Rule of Dominance The trait that is observed in the offspring is the dominant trait (uppercase letters) The trait that is observed in the offspring is the dominant trait (uppercase letters) The trait that disappears in the offspring is the recessive trait (lowercase letters) The trait that disappears in the offspring is the recessive trait (lowercase letters)

14. What did Mendel discover? The Law of Segregation The Law of Segregation The two alleles for a trait must separate when gametes are formed The two alleles for a trait must separate when gametes are formed A parent randomly passes only one allele for each trait to each offspring A parent randomly passes only one allele for each trait to each offspring

15. 2 Flavors of genes: Dominant and Recessive Each parent has two genes (or letters) for a trait. These letters are called alleles. Each parent has two genes (or letters) for a trait. These letters are called alleles. Dominant alleles Dominant alleles Represented in genotypes by CAPITAL LETTERS Represented in genotypes by CAPITAL LETTERS When these alleles are present, they take over or show. When these alleles are present, they take over or show. They are the “stronger” alleles They are the “stronger” alleles Recessive alleles Recessive alleles Represented in genotypes by lower case letters Represented in genotypes by lower case letters They are the “weaker” of the alleles. They are the “weaker” of the alleles.

16. What is homozygous? Both alleles [forms of the gene] are the same Both alleles [forms of the gene] are the same When offspring inherit two dominant genes, (one dominant gene from each parent) they are said to be homozygous dominant (AA) When offspring inherit two dominant genes, (one dominant gene from each parent) they are said to be homozygous dominant (AA) When offspring inherit two recessive genes, (one recessive gene from each parent) they are said to be homozygous recessive (aa) When offspring inherit two recessive genes, (one recessive gene from each parent) they are said to be homozygous recessive (aa)

17. What is heterozygous? When alleles occur in different forms When alleles occur in different forms When offspring inherit one dominant gene and one recessive gene, they are said to be heterozygous (Aa) When offspring inherit one dominant gene and one recessive gene, they are said to be heterozygous (Aa) Since the dominant gene will be expressed, they are said to be heterozygous dominant Since the dominant gene will be expressed, they are said to be heterozygous dominant

18. Co-dominance/ Incomplete Dominance Alleles not dominant or recessive Blend of the traits represented by the two alleles Alleles not dominant or recessive Blend of the traits represented by the two alleles For example: One red allele and one white allele-> pink flower For example: One red allele and one white allele-> pink flower Neither allele is dominant Neither allele is dominant

19. Mendel’s impact Discoveries were ignored throughout the 1800s Discoveries were ignored throughout the 1800s Mendel died never knowing the importance of what he had discovered Mendel died never knowing the importance of what he had discovered Work was reexamined in the early 1900s Work was reexamined in the early 1900s Mendel is the known as the “Father of Genetics” Mendel is the known as the “Father of Genetics”

20. What is genetics? Genetics is the study of how traits are inherited

21. What is a gene? A gene is the basic unit of heredity A gene is the basic unit of heredity Genes hold the information to build and maintain an organism's cells and pass genetic traits to offspring. Genes hold the information to build and maintain an organism's cells and pass genetic traits to offspring.

22. Where do we find these genes? When organisms reproduce, traits are passed from parent to offspring. When organisms reproduce, traits are passed from parent to offspring. These traits are carried in DNA, the genetic material found in a cell’s nucleus. These traits are carried in DNA, the genetic material found in a cell’s nucleus. DNA acts like a blueprint. DNA acts like a blueprint.

23. How are traits passed on?

24. 2 Flavors of genes: Dominant and Recessive Each parent has two genes (or letters) for a trait. These letters are called alleles. Each parent has two genes (or letters) for a trait. These letters are called alleles. Dominant alleles Dominant alleles Represented in genotypes by CAPITAL LETTERS Represented in genotypes by CAPITAL LETTERS When these alleles are present, they take over or show. When these alleles are present, they take over or show. They are the “stronger” alleles They are the “stronger” alleles Recessive alleles Recessive alleles Represented in genotypes by lower case letters Represented in genotypes by lower case letters They are the “weaker” of the alleles. They are the “weaker” of the alleles.

25. Examples of Dominant and recessive traits Tongue-rolling (Roller is dominant, non-roller is recessive) Tongue-rolling (Roller is dominant, non-roller is recessive) Widow’s peak (dominant) Widow’s peak (dominant) Ear Lobes (Unattached is dominant, attached is recessive) Ear Lobes (Unattached is dominant, attached is recessive) ‘Bent’ phalanges (dominant, normal is recessive) ‘Bent’ phalanges (dominant, normal is recessive)

26. How are genes expressed? Genotype – the inherited alleles (letters) Genotype – the inherited alleles (letters) Phenotype – what the alleles look like when inherited. Phenotype – what the alleles look like when inherited.

27. Punnett Squares Using Punnett Squares we can get an idea of what the offspring could look like Using Punnett Squares we can get an idea of what the offspring could look like Allows us to calculate probability of certain genotypes and phenotypes to occur Allows us to calculate probability of certain genotypes and phenotypes to occur

28. A monohybrid cross Using this is a several step process, look at the following example Using this is a several step process, look at the following example Tallness (T) is dominant over shortness (t) in pea plants. A Homozygous tall plant (TT) is crossed with a short plant (tt). What is the genotypic makeup of the offspring? The phenotypic makeup ? Tallness (T) is dominant over shortness (t) in pea plants. A Homozygous tall plant (TT) is crossed with a short plant (tt). What is the genotypic makeup of the offspring? The phenotypic makeup ?

29. The Punnett process 1. Determine alleles of each parent, these are given as TT, and tt respectively. 2. Take each possible allele of each parent, separate them, and place each allele either along the top, or along the side of the punnett square t t T T Alleles for short plant Alleles for tall plant

30. The Punnett process continued 3. Lastly, write the letter for each allele across each column or down each row. The resultant mix is the genotype for the offspring. In this case, each offspring has a Tt (heterozygous tall) genotype, and simply a "Tall" phenotype. t t T T Alleles for short plant Alleles for tall plant Tt

31. The Punnett process continued Here we have some more interesting results: First we now have 3 genotypes (TT, Tt, & tt) in a 1:2:1 genotypic ratio. We now have 2 different phenotypes (Tall & short) in a 3:1 Phenotypic ratio. This is the common outcome from such crosses. Here we have some more interesting results: First we now have 3 genotypes (TT, Tt, & tt) in a 1:2:1 genotypic ratio. We now have 2 different phenotypes (Tall & short) in a 3:1 Phenotypic ratio. This is the common outcome from such crosses. t T T t F1 parent Tt TT tt

32. Determining Gender Female – XX Female – XX Male –XY Male –XY Male determines the sex of the baby Male determines the sex of the baby

33. Creating a pedigree activity

34. Quick Review Genotype=what genes someone has Genotype=what genes someone has Genes are usually represented by a letter, a capital letter for the dominant trait, a small case for the recessive. Genes are usually represented by a letter, a capital letter for the dominant trait, a small case for the recessive. Ex. Tongue Rolling is dominant, so we use R to represent the tongue rolling Ex. Tongue Rolling is dominant, so we use R to represent the tongue rolling Inability to roll your tongue is recessive so we use r to represent the non-rolling gene Inability to roll your tongue is recessive so we use r to represent the non-rolling gene For every trait, you get a gene from each parent For every trait, you get a gene from each parent

35. Genotypes and Phenotypes Mom and Dad are Rr-that is their genotype, they can also be described as heterozygous- they have 1 of each gene Mom and Dad are Rr-that is their genotype, they can also be described as heterozygous- they have 1 of each gene What is their PHENOTYPE? What is their PHENOTYPE? The youngest son has a genotype of rr-he is Homozygous recessive-2 copies of the recessive gene The youngest son has a genotype of rr-he is Homozygous recessive-2 copies of the recessive gene His phenotype? His phenotype?

36. Making a Pedigree chart Pedigree charts are made to chart family history and see how traits are passed Pedigree charts are made to chart family history and see how traits are passed

37. Symbols on a pedigree chart Shade individuals that have the trait you’re studying Shade individuals that have the trait you’re studying Males=squares, Females-circles Males=squares, Females-circles

38. Drawing your pedigree Married-connected at side Married-connected at side Siblings-connected at TOP not at the side (hopefully not siblings AND married) Siblings-connected at TOP not at the side (hopefully not siblings AND married) Oldest child-to the left Oldest child-to the left