2. Think – Pair - Share Selective Breeding People have used selective breeding to improve crops and domestic animals Think of two examples of selective breeding in domestic animals or crops. What particular traits may breeders be looking out for in your examples?

3. Mendel’s Study of Traits Punnett Squares Punnett Squares: predicts the outcome of a genetic cross be considering all possible combinations of gametes in the cross Assists breeders in predicting how often a trait will appear when two organisms are crossed (bred)

5. Punnett Example 1: TT x Tt TT T t TT Tt Tt Genotypes: 50% TT 50% Tt Phenotypes 100% Tall T= Tallt=Short

6. Example 2: Complete the Cross Brown eyes is dominant. Blue eyes is recessive. Cross a homozygous dominant and a homozygous recessive. What percentages of blue-eyed and brown eyed offspring will you get? Use B for brown and b for blue

7. Punnett Example: BB x bb BB b b Bb Bb Bb Genotypes: 100 % Bb Phenotypes 100% Brown Eyed B= Brownb=Blue

8. Example 3: Perform the cross Tongue rolling is a dominant trait. Non tongue rolling is recessive. If the mother is heterozygous and the father is heterozygous- what are their chances of having a child with the tongue rolling ability? Use R for dominant and r for recessive

9. Punnett Example: Rr x Rr Rr R r RR Rr Rr rr Genotypes: 25% RR 50% Rr 25% rr Phenotypes 75% Tongue Rolling 25% Non-tongue Rolling R= Tongue Rolling r= Non-tongue Rolling

10. Intermediate Traits Incomplete Dominance Incomplete Dominance: Usually the dominant trait takes over the recessive In some traits, there can be a “mix” Ex: Red flowers crossed with white flowers = Pink flowers Ex: Straight hair crossed with curly = wavy hair

11. Mendel’s Study of Traits Pedigree Chart What if you wanted to learn about an inherited trait present in your family? Pedigree Chart: Family history that shows how a trait is inherited over generations Useful in tracking genetic disorders to see if an individual is a carrier or may pass it the disorder to their offspring

12. Mendel’s Study of Traits Carrier Carrier: Heterozygous (ex: Cc) for an inherited disorder but does not show symptoms of the disorder

13. Mendel’s Study of Traits Autosomal Traits Occur on chromosomes not related to gender (body cells) Both sexes have same probability of inheriting

14. Mendel’s Study of Traits Sex-linked Traits Trait whose allele is located on X chromosome Most are recessive Males mainly affected because they only have one X chromosome Females usually just carriers (presence of dominant X to mask recessive one) Females would have to be homozygous recessive to show trait (less likely to inherit)

15. Examples: -Colorblindness -Male Baldness -Hemophilia

16. Evaluate the Pedigree Answer the questions in your notes using this Pedigree chart for colorblindness I II III IV

17. Assessment Three Predict the expected phenotypic and genotypic ratios among the offspring of two individuals who are heterozygous for freckles (Ff) by using a punnett square Summarize how a test cross can reveal the genotype of a pea plant with round seeds Calculate the probability that an individual heterozygous for a cleft chin (Cc) and an individual homozygous for a cleft chin (cc) will produce offspring that are homozygous for a cleft chin When analyzing a pedigree, how can you determine if an individual is a carrier (heterozygous) for a trait being studied?

18. Complex Patterns of Heredity Polygenic Trait When several genes influence a trait (all on one chromosome or on different) Ex: Eye color, height, weight, hair and skin color Have degrees of intermediate conditions between extremes Can be complex due to independent assortment and crossing over during meiosis

19. Complex Patterns of Heredity Intermediat e Traits Incomplete dominance- an individual displays a trait that is intermediate between the two parents Ex: white snapdragon x red snapdragon equals pink snapdragon Ex: curly hair x straight hair (both homoz dom) equals wavy hair

20. Complex Patterns of Heredity Multiple Alleles Genes with three or more alleles EX: ABO blood groups A and B refer to carbohydrates on surface of red blood cells, O has none A and B dominant over O, but not over each other (codominant) Can only have 2 of the possibilities for the gene

22. Possible Blood Type Possibilities

24. Complex Patterns of Heredity Codominance 2 dominant alleles are expressed at the same time and both forms of the trait are displayed Ex: AB blood group (has both A and B carbohydrates on the surface of red blood cells)

26. Complex Patterns of Heredity Traits influenced by environment EXAMPLE 1: Hydrangea flowers Blue (acidic soil) to pink (neutral to basic soil)

27. Complex Patterns of Heredity Traits influenced by environment EXAMPLE 2: Arctic Fox During summer, fox produces enzymes that make red brown pigments In cold, pigment producing genes don’t function and coat remains white Fox blends in with snowy white background

28. Complex Patterns of Heredity Traits influenced by environment EXAMPLE 3: Siamese Cats Genotype results in darker fur color in cooler areas of the body (ears, nose, paws, tail darker than rest of body)

29. Complex Patterns of Heredity Traits influenced by environment EXAMPLE 4: Human Height Nutrition and internal environmental conditions

30. Complex Patterns of Heredity Traits influenced by environment EXAMPLE 5: Human Skin Color Exposure to sun

31. Complex Patterns of Heredity Traits influenced by environment EXAMPLE 6: Human Personality Aggression influenced by environment and genes

32. Complex Patterns of Heredity Traits influenced by environment Twins used to study environmental influences because their genes are identical, any differences between them are due to the environment

33. DO NOW Grab a Biology book, turn to page 179 Take out Notes Turn to Pageon genetic disorders Think – Which genetic disorder does this picture represent?

34. Genetic Disorders In order for a person to develop and function normally, proteins encoded in genes must function precisely May have harmful effects produced by inherited mutations Damaged or incorrectly copied genes can result in the production of faulty proteins Mutations are rare, due to efficient correction systems in cells Often carried by recessive alleles in heterozygous individuals and passed down as homozygous alleles in offspring

35. Gallery Walk! Genetic Disorders Each group will be assigned a section Pages 179 - 182 Make a poster in 15 minutes on your section that highlights the IMPORTANT & SIGNIFICANT details of your section Make sure you can answer the questions on your section – if you can’t – add the info! Each group will move around to each section and will have 5 minutes to answer each question

36. Genetic Disorders

37. Sickle Cell Anemia Caused by mutated allele that produces defective form of protein hemoglobin In rbc’s, Hb binds to and transports oxygen Causes sickle shaped red blood cells that rupture easily, clog blood vessels and can’t transport oxygen well Carriers exposed to malaria can prevent infection when they have sickle cell. It kills malaria protozoans and healthy rbc’s can still transport enough oxygen

39. Genetic Disorders Cystic Fibrosis Fatal, recessive trait Most common inherited disorder in Caucasians 1/25 babies are carriers 1/2500 babies have disease No known cure Have defective copy of gene needed to pump Cl in and out of cell Lung airways clog with mucus, liver and pancreas ducts get blocked

41. Genetic Disorders Hemophelia Sex linked trait Impairs blood’s ability to clot Mutation on one of a dozen blood clotting genes on x chromosome is hemophelia A If male receives defect on x chromosome from mother, y chromosome can’t compensate - develops disease

43. Genetic Disorders Treating genetic disorders Most can’t be cured, but can be treated Families with histories of genetic disorders can receive genetic counseling before having kids to assess the risk

44. Genetic Disorders Treating genetic disorders Some genetic disorders can be treated if diagnosed early on Ex: PKU (Phenylketoneuria)- lack enzyme for converting amino acid phenylalanine to tyrosine Can cause severe mental retardation If found immediately right after birth, baby can be given a diet low in phenylalanine to avoid the symptoms Many states require testing newborns for PKU (inexpensive)

46. Genetic Disorders Treating genetic disorders Gene Therapy Replace defective gene with healthy one Isolate copy of the gene and deliver to infected cell by attaching it to a virus Virus with healthy gene enters cell, starts producing healthy protein “Cures” the genetic disorder

48. Genetic Disorders Gene Therapy Tried for cystic fibrosis by using cold virus BUT, most individuals are immune to cold virus and the lung cells rejected it Currently trying with an AAV virus that produces almost no immune response

49. Assessment Four Differentiate between incomplete dominance and codominance Identify two examples of traits that are influenced by environmental conditions Summarize how a genetic disorder can result from a mutation Describe how males inherit hemophelia A nurse states that a person cannot have the blood type ABO. Do you agree or disagree? Explain

50. Genetics Websites OLogy: The Gene Scene