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Easy Ear

Easy Ear. What are the phenotypes of the ear of corn?. Purple, Yellow, Round. What is the Ratio of Phenotypes?. About ~ Purple/Round 3:1 Yellow Round. Determining degrees of freedom (df): Degrees of freedom can be calculated as the number of categories in the problem minus 1.

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Easy Ear

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  1. Easy Ear What are the phenotypes of the ear of corn? Purple, Yellow, Round What is the Ratio of Phenotypes? About ~ Purple/Round 3:1 Yellow Round

  2. Determining degrees of freedom (df): • Degrees of freedom can be calculated as the number of categories in the problem minus 1. • In our ear, there are two categories (purple and yellow); therefore, there is 1 degree of freedom in our example.

  3. Chi Square Table Anything < 3.85 is good, meaning our confidence is high that our results are reliable and not because of some other factor.

  4. Corresponding to the correct number of degrees of freedom at a confidence probability of 95% (0.05). • If our Chi square value is greater than the Chi square value at our desired confidence level, we must reject the null hypothesis and conclude that the difference between observed and expected values is real and not chance. • In this case this means either our genetic hypothesis is wrong (we thought this was the result from a hybrid cross) or our sample size was too small. • Therefore, Lower numbers = higher % your hypothesis was correct.

  5. Hard Ear

  6. There are four grain phenotypes in the ear of genetic corn: Purple & Smooth (A), Purple & Shrunken (B), Yellow & Smooth (C) and Yellow & Shrunken (D). Q. What are the ratios of Phenotypes? Q. Based on those numbers can we determine Dominance and recessive? Q. What is the likely Genotype of the Parental group? PpSs X PpSs

  7. PpSs X PpSs This table shows four different phenotypes with the following fractional ratios: 9/16 Purple & Smooth (blue), 3/16 Purple & Shrunken (red), 3/16 Yellow & Smooth (green), and 1/16 yellow and shrunken (pink).

  8. Chi Square Problem:A large ear of corn has a total of 381 grains, including 216 Purple & Smooth, 79 Purple & Shrunken, 65 Yellow & Smooth, and 21 Yellow & Shrunken..Your Tentative Hypothesis: This ear of corn was produced by a dihybrid cross (PpSs x PpSs) involving two pairs of heterozygous genes resulting in a theoretical (expected) ratio of 9:3:3:1.Objective: Test your hypothesis using chi square and probability values. In order to test your hypothesis you must fill in the columns in the following the table.

  9. Table 2. Chi Square Data

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