High School Participant Guide - PDF Free Download

High School Participant Guide 1

Analyzing Curriculum and Instruction in relation to the Arkansas K-12 Science Standards Title and grade of lesson: Big ideas in the lesson Connections to Disciplinary Core Ideas (DCI) Science and Engineering Practices Included: Yes/No At Grade Level: Yes/No What more could be included to connect to the practices? 1. Ask questions/define problems 2. Develop and use models 3. Plan and carry out investigations 4. Analyze and interpret data 5. Use math/computation 6. Construct explanations and design solutions 7. Argue with evidence 8. Obtain, evaluate and communicate information Key question A: How is or could engineering be incorporated into the lesson? 11

Crosscutting concepts 1. Patterns 2. Cause and effect 3. Scale, proportion and quantity 4. Systems and system models 5. Energy and matter in systems 6. Structure and function 7. Stability and change of systems Which can be found in this lesson? What more could be included to connect to the cc? Key Question B: How is the nature of science addressed in the lesson? 12

The Making Got Lactase? of the Fittest: The Making of the Fittest: Natural The Selection Co-evolution and Adaptation of Genes and Culture Natural Selection and Adaptation LESSON STUDENT HANDOUT PEDIGREES AND THE INHERITANCE OF LACTOSE INTOLERANCE INTRODUCTION A defining characteristic of mammals is that mothers produce milk for their infants through a process called lactation. Mother s milk is packed with the proteins, fats, and carbohydrates that support the baby s growth and development. The main carbohydrate in milk is the sugar lactose, which is a disaccharide. Infant mammals produce the enzyme lactase in their small intestines, which breaks down lactose into glucose and galactose. The two simpler sugars, or monosaccharides, are easily absorbed through the small intestine and into the bloodstream. The blood delivers the sugars throughout the body to provide cells with a source of energy. At around the time that children stop drinking their mother s milk, most of them also stop producing lactase. If lactase is not produced and a person drinks milk, undigested lactose travels from the small intestine to the large intestine, where it is digested by bacteria. When this happens, a person could have abdominal pain, bloating, flatulence, and diarrhea. Individuals with these symptoms are lactose intolerant. Figure 1. If lactase is produced, the lactose in milk is digested into glucose and galactose in the small intestine. If lactase is not produced, undigested lactose goes from the small intestine to the large intestine, where it is digested by bacteria through fermentation. That process results in the production of various gases and acids that can cause discomfort. Only a minority of human adults 35% of the global human population continues to produce lactase into adulthood. These individuals are lactase persistent, meaning that lactase production persists beyond childhood. (They are also usually lactose tolerant, meaning that they don t have any problems when they drink milk.) Genetic studies suggest that lactose tolerance arose among human populations in the last 7,000 to 9,000 years. This is also when humans began domesticating animals like cows, goats, and camels and started drinking their milk. Pedigrees and the Inheritance of Lactose Intolerance www.biointeractive.org 13 Updated March 2015 Page 1 of 9

Got Lactase? The Co-evolution of Genes and Culture LESSON STUDENT HANDOUT The film Got Lactase? The Co-evolution of Genes and Culture traces the evolution of lactose tolerance. It also describes how researchers analyzed the pedigrees of several Finnish families to identify the changes in the DNA, or mutations, responsible for this trait. In this activity, you will analyze some of those pedigrees to determine how the lactose tolerant trait is inherited. You will then analyze DNA sequences to identify mutations associated with the trait. PROCEDURE Part 1: Determining the Pattern of Inheritance of Lactose Tolerance/Intolerance To determine how lactose tolerance/intolerance is inherited, researchers examined nine extended Finnish families for five generations. Below is one of those pedigrees. Look at the pedigree and then answer the questions below. (For a refresher on pedigrees, refer to Appendix A on the last page of this document.) Figure 2. Pedigree of Family A. (Adapted from a figure in Enattah, N. S., et al. 2002 Nature Genetics 30: 233-237.) 1. Based on the pedigree above, which of the following terms are appropriate for describing the inheritance of the lactose-intolerance trait (filled-in symbols)? Check all that apply. Recessive Inherited Dominant X-linked Pedigrees and the Inheritance of Lactose Intolerance www.biointeractive.org 14 Page 2 of 9

Got Lactase? The Co-evolution of Genes and Culture LESSON STUDENT HANDOUT 2. Which of the following terms are appropriate for describing the inheritance of the lactose-tolerance trait (empty symbols)? Check all that apply. Recessive Inherited Dominant X-linked 3. Use the data in the pedigree and the terms listed in questions 1 and 2 to make a claim about how lactose intolerance is inherited. Provide at least two pieces of evidence in support of your claim. 4. How comfortable are you with drawing a firm claim about the inheritance of lactose intolerance? What might you do next to increase your confidence in making this claim? 5. Study Individuals 5 and 6 of Generation III in Family A and their child. The two parents are lactose tolerant, yet their son is lactose intolerant. Are these data consistent or inconsistent with the claim you made in question 3? Explain your answer. Pedigrees and the Inheritance of Lactose Intolerance www.biointeractive.org 15 Page 3 of 9

Got Lactase? The Co-evolution of Genes and Culture LESSON STUDENT HANDOUT You are now going to examine three additional pedigrees from the Finnish study. Figure 3. Pedigrees of Families B, C, and D. (Adapted from a figure in Enattah, N. S., et al. 2002 Nature Genetics 30: 233-237.) Pedigrees and the Inheritance of Lactose Intolerance www.biointeractive.org 16 Page 4 of 9

Got Lactase? The Co-evolution of Genes and Culture LESSON STUDENT HANDOUT 6. Do the data presented in these additional pedigrees support your claim in question 3 above? Explain your answer. 7. Based on your claim, which symbols would you use to represent the genotype of an individual who is lactose tolerant? Lactose intolerant? 8. Based on your claim, what is the genotype of Individual 3, Generation IV in Family C? Explain your answer. 9. Based on the same claim, what is the genotype of the father of Individual 4, Generation IV in Family D? Explain your answer. 10. Individuals 8 and 9, Generation IV in Family B are sisters. Based on your inheritance claims, what is/are the possible genotype(s) of: a. Individual 9? b. Individual 8? c. The parents of Individuals 8 and 9? 11. Individual 4, Generation IV in Family B is the sister of Individuals 8 and 9 in the question above. What is the probability that Individual 4 is homozygous? Heterozygous? Pedigrees and the Inheritance of Lactose Intolerance www.biointeractive.org 17 Page 5 of 9

Got Lactase? The Co-evolution of Genes and Culture LESSON TEACHER MATERIALS Pedigrees and the Inheritance 18 of Lactose Intolerance www.biointeractive.org Page 9 of 9

Exploring Patterns of Lactase Persistence Name: Work as a group to explore patterns of lactase persistence in people from different parts of the world. Part A: Investigating Geographic Patterns 1. Graphs indicating the percentage of people who are lactase persistent or lactase nonpersistent are in Figure 1. Examine the percentage of people who are lactase nonpersistent and lactase persistent in each region. Write that information in Table 1. Figure 1. Graphs of percentage of lactase persistence by region. West Africa East Africa Percent 100 90 80 70 60 50 40 30 20 10 0 Lactase Persistent Lactase Nonpersistent Percent 100 90 80 70 60 50 40 30 20 10 0 Lactase Persistent Lactase Nonpersistent Middle East 1 Middle East 2 100 90 80 70 100 90 80 70 Percent 60 50 40 Percent 60 50 40 30 30 20 20 10 10 0 Lactase Persistent Lactase Nonpersistent 0 Lactase Persistent Lactase Nonpersistent (Continued) Copyright 2011 BSCS Master 2.13 (Page 1 of 3) Permission granted for classroom use 20

Figure 1. (Continued) Northern Europe Southern Europe 100 90 80 100 90 80 Percent 70 60 50 40 30 20 10 Percent 70 60 50 40 30 20 10 0 Lactase Persistent Lactase Nonpersistent 0 Lactase Persistent Lactase Nonpersistent East Asia 100 90 80 70 Percent 60 50 40 30 20 10 0 Lactase Persistent Lactase Nonpersistent Table 1. Summary of Geographic Patterns of Lactase Persistence Region Lactase persistent (%) Lactase nonpersistent (%) West Africa East Africa Middle East 1 Middle East 2 Northern Europe Southern Europe East Asia 2. Make a claim about whether or not lactase persistence varies geographically. Make sure your claim links to the evidence in Table 1. Copyright 2011 BSCS Master 2.13 (Page 2 of 3) Permission granted for classroom use 21

Part B: Investigating the Role of Gender 1. Examine Table 2, which shows the number of males and females who are lactase persistent or lactase nonpersistent for the complete lactase results. Table 2. Lactase Persistence and Gender Summary Gender Lactase persistent Lactase nonpersistent Male 56 94 Female 52 98 2. Use the data in the table to make a claim about whether or not lactase persistence is more common in males or females. Part C: Investigating the Differences Between Adults and Infants 1. Examine the following table, which shows patterns of lactase activity in adults and infants for the complete lactase results. Table 3. Lactase Persistence and Age Summary Table Age Lactase activity (infants) or lactase persistent (adults) No lactase activity (infants) or lactase nonpersistent (adults) Infants 299 1 Adults 108 192 2. Why do you think there s a difference between adults and infants for lactase activity? Copyright 2011 BSCS Master 2.13 (Page 3 of 3) Permission granted for classroom use 22

Lactose Intolerance, Lactase Persistence and Evolution Part 1 Lactose is a type of sugar found only in milk and milk products. It is a disaccharide composed of two simple sugars - glucose and galactose - which are monosaccharides. Only monosaccharides can be absorbed by the intestine and passed on into the bloodstream. Lactose intolerance is the body s inability to properly digest lactose, due to a lack of lactase in the body. Lactase is an enzyme found in the lining of the small intestine that acts as a catalyst in the breakup of lactose into glucose and galactose, which are easily digested by the body. Lactose intolerance is not an allergy because it s not the immune system responding to the milk (some people however, do have an allergy to milk products which is not associated with lactose). Instead, people who are lactose intolerant cannot digest lactose and the enzyme that does lactase stops being produced when a person is between two and five years old. Most mammals, including humans, have high intestinal lactase activity at birth - which makes sense when you consider nearly all mammals nurse during their first few months. But, in many cases, this activity declines to low levels during childhood and drops even further - or completely disappears - in adulthood. The low lactase levels cause incomplete digestion of milk and other foods containing lactose. Undigested lactose in the bowel then is subject to fermentation by bacteria that cause the bloating, gas, constipation, diarrhea, and cramping associated with lactose intolerance. 23

Part 2 Lactase persistence means that lactase production persists beyond childhood. Only a minority of human adults 35% of the global human population continues to produce lactase into adulthood and can drink milk without any problems. An estimated 90% of people of north European descent are lactase persistent while only 5% of people of East Asian descent are. Regardless of our ancestry, most of us began our lives drinking milk from a bottle or breast so what happened? Why do so many babies enjoy lactose and so many adults worldwide avoid it? Anyone who drank milk as a baby carries a working version of the gene that codes for lactase. In lactase persistent individuals the gene that codes for lactase keeps working into adulthood while those who are lactose intolerant, that lactase gene is switched off after weaning. Mutations keep the lactase gene permanently switched on. Multiple lines of evidence from human genetics, cattle genetics, and archaeological records suggest that Middle Eastern and North Africans populations domesticated cattle between 7,000 and 9,000 years ago, and that these animals were later brought into Europe. In that domesticated cattle environment, being able to drink milk directly - instead of having to process it into lower-lactose cheese - would have been advantageous, providing additional sustenance and, during droughts, a source of water. The lactase persistent mutation arose randomly - as all mutations do, but once it arose, it had a distinct advantage in these populations. Natural selection would have favored individuals carrying the lactase persistent mutation, spreading it through ancient European populations that depended on dairying. Recent evidence suggests that cattle may have been domesticated independently in several places, including Africa. As African populations began herding cattle, lactase persistence became an advantageous trait. Research into the evolutionary origins of lactase persistence illuminates some fascinating aspects of human evolutionary history. The convergent evolution of African and European populations in relation to cattle domestication reveals that shared aspects of human culture across different ethnic groups affects our evolution in similar ways. 24

Resources for ADE High School Professional Development Science Take-out Enzymes and Lactose Intolerance, Kit is $14.00 or unassembled 10 kits $98.00, http://www.sciencetakeout.com hhmi BioInteractive Got Lactase? The Co-evolution of Genes and Culture: Pedigrees and the Inheritance of Lactose Intolerance, http://www.hhmi.org/biointeractive/pedigrees-and-inheritance-lactoseintolerance hhmi BioInteractive Got Lactase? The Co-evolution of Genes and Culture: The Making of the Fittest Video, http://www.hhmi.org/biointeractive/film-guides-gotlactase-co-evolution-genes-and-culture National Institutes of Health Evolution and Medicine Free download or supplement, https://science.education.nih.gov/customers/hsevolution.html Framework for K-12 Science Education: Free PDF http://www.nap.edu/catalog/13165/a-framework-for-k-12-science-educationpractices-crosscutting-concepts New Arkansas Science Standards: Free Download http://www.arkansased.gov/divisions/learning-services/curriculum-andinstruction/curriculum-framework-documents/science Next Generation Science Standards: http://www.nextgenscience.org/ National Science Teachers Association NGSS resources: http://ngss.nsta.org/ 27