Lab #1: Population Genetics by Azeem Jimoh and Joseph Yau
Genetic variance of the bean tribe and Natural selection of the bead population.
By Joseph Yau and Azeem Jimoh
Part A: For part A, our hypothesis was, for a population not affected by the process of natural selection,
the Distribution of genes, our Ho, should have a Mendelian ratio which in this case should be,
25% homozygous white, 25% homozygous speckled, and 50% heterozygous. For our alternate hypothesis,
the results should be out of Mendelian ratios. Our prediction was that the genes should look very similar
to our alternate hypothesis this.
the Distribution of genes, our Ho, should have a Mendelian ratio which in this case should be,
25% homozygous white, 25% homozygous speckled, and 50% heterozygous. For our alternate hypothesis,
the results should be out of Mendelian ratios. Our prediction was that the genes should look very similar
to our alternate hypothesis this.
Figure 1: Beans and Beads shown in cup before selection
Figure 2: Displays the genotypes present in population and the offspring who possess said
genotypes. Genotypes were determined by picking two beans from a cup, and the combination of the two would be the genotype.
genotypes. Genotypes were determined by picking two beans from a cup, and the combination of the two would be the genotype.
Analysis: According to our hypothesis, our experiment should of had 25% homozygous white, 25% homozygous speckled, and 50% heterozygous,
which when using a population of 50 would translate to 12.5,12.5, and 25 respectively. However when you look at the data in Figure 1, you would see
that homozygous white has 16 beans pairs, heterozygous has 16 pairs, and homozygous speckled has 18 pairs. This data is does not resemble our data,
and rejects our hypothesis and instead supports our alternate hypothesis.In our hypothesis it was claimed that our results should resemble our Ho,
meaning that it should have Mendelian ratio.But, if you were to perform a chi-squared calculation of all our data using our data and our expected results,
you end up with 6.64 which surpass our limit of 5.99 with a degree freedom of 2. With our chi-squared being over the limit of 6.99, we can say this specific
experiment rejects both hypothesis and our Ho and instead supports our alternate hypothesis. The most likely reason on why we have these results is,
when selecting beans, the speckled beans were a lot larger than the white beans. So when we went to grab the beans, our hands most likely gravitated towards
the easier to pick up larger beans.
which when using a population of 50 would translate to 12.5,12.5, and 25 respectively. However when you look at the data in Figure 1, you would see
that homozygous white has 16 beans pairs, heterozygous has 16 pairs, and homozygous speckled has 18 pairs. This data is does not resemble our data,
and rejects our hypothesis and instead supports our alternate hypothesis.In our hypothesis it was claimed that our results should resemble our Ho,
meaning that it should have Mendelian ratio.But, if you were to perform a chi-squared calculation of all our data using our data and our expected results,
you end up with 6.64 which surpass our limit of 5.99 with a degree freedom of 2. With our chi-squared being over the limit of 6.99, we can say this specific
experiment rejects both hypothesis and our Ho and instead supports our alternate hypothesis. The most likely reason on why we have these results is,
when selecting beans, the speckled beans were a lot larger than the white beans. So when we went to grab the beans, our hands most likely gravitated towards
the easier to pick up larger beans.
Part B:
Hypothesis
In Part Two of the experiment, the gene pool which contains 25 beads of 4 colors was separated randomly to two populations. The population that we were responsible
for was consisted of 11 red beads, 15 white beads, 15 clear beads and 9 blue beads. As genetic drift is random, after doubling the population and randomly select the
next generation for 9 more generation, the 10th generation should be the same. As a result, the hypothesis was set as the allele frequencies same as the first generation.
For our alternate hypothesis, our generation 10 should have a different amount of beads and be passed the Chi squared limit.For our prediction, we predicted that not only
would the beads in generation 10 not match the generation 1 beads, but there would be a dominant bead that has a significant number over the rest of them.
for was consisted of 11 red beads, 15 white beads, 15 clear beads and 9 blue beads. As genetic drift is random, after doubling the population and randomly select the
next generation for 9 more generation, the 10th generation should be the same. As a result, the hypothesis was set as the allele frequencies same as the first generation.
For our alternate hypothesis, our generation 10 should have a different amount of beads and be passed the Chi squared limit.For our prediction, we predicted that not only
would the beads in generation 10 not match the generation 1 beads, but there would be a dominant bead that has a significant number over the rest of them.
Figure 3: Depicts beads sorted out after being randomly selected from generation 1.
The results were recorded then the process was repeated until 10 generations were made.
is 11 red beads, 15 white beads, 15 clear beads and 9 blue beads.
Data
Figure 4:The change of number of beads, which represents the allele sequence, after repeating 10 generation
Analysis
Chi-squared calculations:
The degree of freedom is 4-1-0=3
The critical number of 
at p=0.05 and DF=3 is 7.82
at p=0.05 and DF=3 is 7.82
As the calculated 
exceeds the critical number, the null hypothesis is rejected.
exceeds the critical number, the null hypothesis is rejected.
Conclusion
From the data of the experiment, there is no significant change in the first five generation. However, the number of red beads was recorded to be the largest portion in
the generation in the sixth generation. After that, the number of red beads became the dominant group in the generation.
the generation in the sixth generation. After that, the number of red beads became the dominant group in the generation.
The whole process was designed to simulate genetic drift, which is a random process. However, after a dominant allele exists in the generation, the chance of red beads being
selected dramatically increase. From that point, the data does not agree to the hypothesis which is then showed to be rejected in the calculation.
selected dramatically increase. From that point, the data does not agree to the hypothesis which is then showed to be rejected in the calculation.
Very interesting to see how your data differs from Jason's and my data since you guys split with us to make the first generation!
ReplyDeleteAlso, shouldn't the deviation for Chi-squared be 5.99 not 6.99? Maybe just a typo or me recording something wrong just want to make sure!
This is Severin posting above by the way, still figuring this out
DeleteAmazing. The first report I read that rejects the null hypothesis in the first exercise. However the stated hypothesis was not clear but your group's data and chi-square calculations rejects the null hypothesis, and my group failed to reject the null hypothesis. The second exercise demonstrated genetic drift that happens due to a random chance or sampling error, and it was interesting to see that there was no change in the number of allele frequency in the first five generations. It makes wonder whether it was due to biases in selection or the change in the frequency happened by chance after the 5th generation!.
ReplyDeleteCompared your group's data and conclusion in Part B with ours, I noticed that no matter using beans or beads, both of our hypothesis were rejected. However, using beads reduce the chi-square since the sizes of the beads are similar. On the contrary, shapes and sizes of different beans greatly influenced the result of this experience. Obviously, the bigger beans will eventually become the dominant population.
ReplyDeleteOur data of part A is the same as yours while part B is not. For part A, we found the same problem that we tended to get speckled bean due to its larger size. But our data is more obviously that we got 25 of homo speckled. For part B, we predicted generation 10 should be 25 for each color, and the data collected truly support it. But on the other hand, since your data rejects ours, I wonder if human factors are not purely random .
ReplyDeleteThat's pretty rad that for part A it is out of HWE and Mendelian Genetics. I wonder if maybe using something else to pick out the beans instead of just your hands to eliminate some of the bias would have changed the outcome much. Because for ours we used tongs to grab the beans and we were almost exact for HWE.
ReplyDeleteHey guys, I thought it was interesting now the chart changed throughout the experiment. I was really intrigued on how the red beads constantly increased, but the blue increased for the first couple generations then decreased dramatically. This could be related to the real world and populations in ecosystems. One could follow an animal for 4 generations and could see an increase and a population thrive. But after the generation viewed, their population can decrease by ¼.
ReplyDelete