Copy of 2024 Human Genetics Lab

Human Genetics Lab Access the Human Genetics Lab Slideshow Objective: Are your traits unique? Hypothesis: Review the Traits Table 1. Observe the people around you to predict what overall percentage of dominant vs. recessive traits. 2. Write a Hypothesis that incorporates your prediction (% dominant traits) for yourself and for the class (% of people with more dominant traits) I think I will have more recessive traits than dominant traits and I think the class as a whole will have more dominant traits than recessive. Materials: PTC paper, class Directions: Place a “D” or “r” in the Me column for the trait that describes you. Write the class numbers. Tell whether the trait is dominant or recessive. TRAITS TABLE TRAIT Me Class/ DOM Class/ REC 1. Tongue rolling (dominant) R 28 7 2. Bent little fingers (dominant) R 14 21 3. Widow's peak (dominant) R 5 30 4. Hitchhiker's thumb (recessive) R 21 14 5. Hand clasp (L. thumb over R.- dominant) D 25 10 6. Arm folding (R. over L. – dominant) D 25 10 7. Free earlobe (dominant) D 24 11

8. Chin cleft (dominant) R 3 32 9. Hair on mid-finger joints (dominant) R 3 32 10. Long Second toe (dominant) D 8 27 11. Ear points (dominant) D 20 15 12. Dimples (dominant) D 18 17 13. Curly hair (dominant) D 18 17 14. Index finger shorter than ring finger (dominant) R 28 7 15. Eye Color (Brown or Black is dominant) D 30 5 16. PTC Taster (Dominant) D 30 5 Totals (dominant vs recessive) See Below 301 259 Final Percentages: See Below 53.8% 46.3% Calculate your percentage of dominant and recessive traits #dom/16 X 100 = ____56.3_____% #rec/16 X 100 = ____43.8_____% Compare with the class %’s Genetic Wheel Directions: ● Fill In the Gene Wheel Below ● Start in the center; Color in the space of your trait ● Move to the next circle based on your trait; Color your trait ● Keep following your traits until you reach the outside of the circle ● Your number is on the outside of the wheel ● Determine your number using the Genetics Wheel.

Analysis and Conclusion Questions: 1. Graph your results: Create a graph that shows the percentage of Dominant and Recessive Traits for you and the class. Insert graph here: 2. Make a Claim, Evidence, and Reasoning based on the evidence of your graph. I had a higher dominant trait percentage than the rest of the class did. This can be seen through the graph which shows the darker blue colored bar which is a little bit higher than the lighter blue colored bar. The darker colored bar represents me and the lighter colored bar represents the rest of the class. Because the darker colored bar is higher, this shows that it had a larger percentage of dominant traits because the longer the bar the higher the percentage. Go to: PTC the Genetics of Bitter Taste 3. List some interesting facts (at least 5) you learned about PTC and why you found them interesting. 1. The whole reason the PTC gene was discovered was because one of Dr. Fox’s colleagues did not like the taste of something that Dr. Fox himself could not taste. I found this interesting because it amazed me how something so irrelevant was the cause of us discovering the PTC gene. 2. The PTC gene, TAS2R38, was discovered in 2003. This surprised me because it is pretty recent compared to when I thought it was

discovered. 3. Although PTC is not found in nature, the ability to taste it correlates strongly with the ability to taste other bitter substances that do occur naturally, many of which are toxins. I found this peculiar because this theory can be used throughout nature even if PTC can't be naturally found in the wild. 4. The ability to discern bitter tastes evolved as a mechanism to prevent early humans from eating poisonous plants. I found this interesting because it is a shunned part of evolution and I had never heard of it. 5. The ability to taste PTC and preferences for certain types of food may be why some of us think that broccoli is just too bitter to eat. I found this interesting because it showed how something as insignificant as the PTC gene can be used to find why people dislike certain foods. Go to: Myths of Human Genetics 4. Write a paragraph explaining why this lab is misleading when learning about genetics. ● Explain why the traits are sometimes difficult to assess in terms of dominant vs. recessive. ● Propose a reason why some of the traits listed as being dominant might not show up that frequently in the American Population. ● What kinds of human traits could be better to study? ● Why does the author think it would be better to study cat fur? The “Myths of Human Genetics” lab, as well, has some traps for students in terms that when learning about genetics it simplifies the inheritance complexities. Although it describes characteristics as dominant and recessive, the fact is that many of them are polygenic – affected by several genes- which may be further complicated with environmental factors. This complexity has, therefore, made it almost impossible to judge traits on a simple basis of dominant versus recessive. A number of traits that are listed as dominant may actually occur rarely in the American population, due to factors such as genetic variety, population bottlenecks or selective stresses. Rather than only studying human traits, a wider range of trait studies in different species – such as cat fur genetics for example- can offer more detailed insight into the nature of genes. The author implies that cat fur should be studied since it presents more observable characteristics under the influence of a simpler genetic make up which is easier to study and understand patterns in genetics. 5. Select 2 of the traits listed in the left margin of " Myths of Human Genetics " web page. Please answer the following questions for each trait you selected. Write your answers in complete paragraph form ● What is the trait you chose to study? ● Why did you choose that trait? ● What is the myth about that trait? ● What is probably the truth about that trait? ● How does our class data support or deny the probable truth?