Real World Learning Objects: Science Print...
 
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Human Genetics and the Dominant Trait
BACKGROUND INFORMATION:

In a given population, is the dominant trait the most frequently occurring? One way to find out would be to participate in the Human Genetics: A Worldwide Search for the Dominant Trait telecollaborative project and ask a lot of people all over the world which traits they have and then analyze the collected data to see if the dominant trait occurs more frequently than the recessive trait. This telecollaborative project is geared to high school students and is run twice a year, in the fall and spring.

While this experience can be both exciting and an authentic learning experience, it unfortunately may take longer to implement in a college course than the time allotted. Therefore for this activity, you will make predictions and conduct a brief genetic survey with peers in your classroom by analyzing several common dominant / recessive traits and then use archived data collected from the Human Genetics project to determine if dominant traits occur more frequently.

  1. Introduction to Human Genetics: Dominant & Recessive Traits
    1. Review the following slides from the short PowerPoint presentation "Human Genetics: Dominant & Recessive Traits" individually, with a partner, or as a class: genetics.ppt - 551 KB

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    2. Find a partner or individually determine whether or not you have the dominant or recessive trait for each of the traits. Write down the genetic trait you possess and if it is dominant or recessive for each of the characteristics.
      1. Earlobes:
      2. Thumbs:
      3. Pinky:
      4. White Forelock:
         
    3. Based on your observations so far, do you think dominant trait is the most frequently occurring in a given population? Why or why not?








       
  2. Class Poll: Conduct a Brief Genetic Survey
    1. Download the following Excel spreadsheet and conduct a simple poll of everyone in your class to see how many of your peers have the dominant or recessive traits (NOTE: optionally, you can tally up the responses and keep track of them on paper).
      • genetics_worksheet.xls - 18 KB (change the "Total Number in Sample" to the number of students participating in this class poll).
    2. Were your previous hypotheses correct? Explain why you think they were or were not.



       
    3. While interesting, these results are not conclusive. Why do you need more data to make a more definitive conclusion?





       
  3. Increasing the Survey Population: The Human Genetics Project
    Human Genetics: A Worldwide Search for the Dominant Trait is a telecollaborative project implemented twice a year, every year where classes from around the world compare these and other common genetic traits.
    1. Download and analyze the archived data accumulated from schools participating in this project since 1998: cumulativedata.xls - 7.5 KB
    2. Calculate the percentage for the dominant and recessive characteristics for each of the surveyed traits:
        Earlobes Thumb Pinky White Forelock
      Total Free Attached Total Straight Curved Total Bent Straight Total With Without
      Totals                        
      Percentage 100%     100%     100%     100%    

       

    3. Based on this data, is the dominant trait the most frequently occurring? Why or why not?






       
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