Population Genetics: At Home Demonstration Instructions MATERIALS NEEDED 20 coin
ID: 185296 • Letter: P
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Population Genetics: At Home Demonstration Instructions MATERIALS NEEDED 20 coins/beads/marbles/playing cards/pieces of paper of one color 20 coins/beads/marbles/playing cards/pieces of paper of a second color Brown paper or cloth bag (cannot be see through) Calculator INSTRUCTIONS In this demonstration you will be tracking allele frequencies while either following all five Hardy-Weinberg conditions or violating some of them. You will not be using the Hardy-Weinberg equation because you will be able to see the genotype of each individual. The next item in this module is a worksheet on which you should record your data for each demonstration. It is best to print out a copy to fill in by hand as you go, then type up the results later to submit through the Dropbox at the end of this module. Remember to take two pictures to show that you did the demonstration. Include a piece of paper with your name on it in each picture to prove it is yours. Proper Hardy-Weinberg Conditions 1. Start by placing 10 of each colored object into your bag. (ex. 10 recd playing cards and 10 black cards) Decide which color will be dominant and which will be recessive. Calculate the starting values for p and q. Remember, p is the percent (as a decimal) of dominant alleles out of the total alleles, while qis the percent (as a decimal) of recessive alleles out of the total alleles. 2. Mix up the objects in the bag and pull out a pair. Record the genotype in your Activity Sheet. Place the objects back in the bag, mix again, and pull out another pair. Continue drawing, recording, and returning until you have 30 offspring. (You may find it useful to record using tick marks in three columns labeled AA, Aa, and aa in the Activity Sheet) 3. Calculate the new p and q for your population. Remember, the Hardy Weinberg equation is: p+2pq+q'-1. This is the same as saying "The proportion AA individuals+the proportion of Aa 4.Explanation / Answer
#Demonstration 1
Generation 1
Offspring nos. AA = 10 Aa = 7 aa = 13
Total 'A' alleles = 27 Total 'a' alleles =33
New 'p' = ..45 New 'q' = .55
New number of dominant objects = 17 New number of recessive objects = 13
Generation 2
Offspring nos. AA = 6 Aa = 14 aa=10
Total 'A' alleles = 26 Total 'a' alleles =34
New 'p' = 0.43 New 'q' =0..57
New number of dominant objects = 20 New number of recessive objects= 10
Generation 3
Offspring nos. AA = 5 Aa = 12 aa= 13
Total 'A' alleles = 22 Total 'a' alleles =38
New 'p' = 0.36 New 'q' = 0.64
New number of dominant objects = 17 New number of recessive objects = 13
Initial the values of p and q were .5 but with generations changes in p and q are evident. also an increase in the presence of 'a' allele is observed. Thus we can say evolution has occured.
#Demonstration 2
Generation 1
Offspring nos. AA = 3 Aa = 5 aa= 2
Total 'A' alleles = 11 Total 'a' alleles = 9
New 'p' = 0.55 New 'q' =0.45
New number of dominant objects = 8 New number of recessive objects = 2
Generation 2
Offspring nos. AA = 4 Aa = 4 aa = 2
Total 'A' alleles = 12 Total 'a' alleles = 8
New 'p' = 0.6 New 'q' = 0.4
New number of dominant objects = 8 New number of recessive objects = 2
Generation 3
Offspring nos. AA = 3 Aa = 6 aa= 1
Total 'A' alleles = 12 Total 'a' alleles = 8
New 'p' = 0.6 New 'q' = 0.4
New number of dominant objects = 9 New number of recessive objects = 1
The values of p and q are pretty close to .5 hence we can say significant evolution has not occured.
#Demonstration 3
Generation 1
Offspring nos. AA = 14 Aa = 16 aa= 0
Total 'A' alleles = 44 Total 'a' alleles = 16
New 'p' = 0.73 New 'q' = 0.27
New number of dominant objects = 30 New number of recessive objects = 0
Generation 2
Offspring nos. AA = 20 Aa = 10 aa= 0
Total 'A' alleles = 50 Total 'a' alleles = 10
New 'p' = 0.83 New 'q' = 0.17
New number of dominant objects = 60 New number of recessive objects = 0
Generation 3
Offspring nos. AA = 22 Aa = 8 aa= 0
Total 'A' alleles = 52 Total 'a' alleles = 8
New 'p' = 0.87 New 'q' = 0.13
New number of dominant objects = 60 New number of recessive objects = 0
Significant change is observed and the amount of 'a' allele has dropped significantly in the population. Hence the dominant feature is more favoured and thus evolution has occured