2. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Concordance When both twins express the same trait

3. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning

5. Survey of Multifactorial Traits Obesity Cardiovascular disease Skin Color Intelligence

6. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Obesity Serious health concern Twin studies estimate heritability close to 70% Adoption studies estimate heritability around 30% Fig. 5.11

7. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Obesity predisposes to higher risks of: Type II diabetes Hypertension Coronary heart disease Osteoarthritis Cancers Measured by BMI = weight (kg)/height (m) 2 >30 BMI considered obese

8. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Credit: © Dr. Daniel Eitzman/Visuals Unlimited 350882 ob/ob mouse

9. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Experiments with parabiotic mice

10. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning ob - Leptin db - Leptin receptor

11. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Weight homeostasis

12. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning P = G + E

13. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Genes for Obesity Several identified genes in mice Weight controlling hormone leptin Human genes – Gene for leptin maps to chromosome 1p31 – Mutations account for small percentage (~5%) of obesity cases – Important genes for obesity are located on numerous chromosomes

14. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Gut flora affecting obesity? nature.com

15. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Gut flora affecting obesity? Bacteria digest complex polysaccharides Make more nutrients (i.e. more calories) available to host Lean mice/humans Obese mice/humans More Bacteroidetes, Less Firmicutes More Firmicutes, Less Bacteroidetes Inject gut flora from lean mice to obese mice - get leaner!!!

16. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Risk Factors for Cardiovascular Disease –Heredity –Male –Hypertension –High LDL or low HDL –Smoking –Obesity –Lack of exercise –Stress http://academic.brooklyn.cuny.edu/biology/bio4fv/page/ldl.gif

17. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Genetic Disorders Associated with Cardiovascular Disease Angiotensinogen gene Familial hypercholesterolemia Autosomal dominant defective or absent LDL receptors Numerous others

18. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Atherosclerosis Credit: © Carolina Biological/Visuals Unlimited 214424

19. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Skin color Controlled by more than two genes Fig. 5.18

20. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Skin Color Fig. 5.19

21. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Intelligence Intelligence quotient (IQ) Currently no objective way to quantify components of intelligence IQ values are heritable –Heritability for IQ range 0.6 to 0.8 General cognitive ability Quantitative trait loci (QTLs)

22. Chapter 5 Human Heredity by Michael Cummings ©2006 Brooks/Cole-Thomson Learning Correlation in IQ Measurements Fig. 5.21