Examining Of Mendelian Genetics And Its Laws

This experiment was designed to help us learn and examine Mendelian genetics and its Laws through example, along with demonstrating how we are to go about solving problems presented by monohybrid crosses. The two laws are the Law of Segregation and the Law of Independent Assortment. For starters, the Law of Segregation implies that the two alleles in heritable attributes will separate from one another to fill in different gametes from each other.

As for the second law, the Law of Independent Assortment, it is stated that genes may sort themselves independently, which means that each pair of alleles segregate independently instead of in pairs during gamete formation (Campbell, 2017). For this experiment, we were to count the various kernels on a corncob to determine the genotype for the kernels, and with this data we were able to form a Chi-Squared test in order to determine the actual result. Another short part of our experiment worth mentioning involved counting the seedlings of a mungbean plant, tallying up how many seedlings were green or albino, then determining the ratio between both.

The importance of this entire experiment is that it allows us to view a comprehensive set of information to show that, in Mendelian genetics, no two sets of data will ultimately be the same. With our ear of corn, we were able to view the effects of cross breeding different corn plants and what genes were dominant or recessive in the creation of our particular piece of corn. As for a hypothesis, there are a couple; the overall color of the seedling should follow the laws of inheritance, while the phenotypes represented in the kernels should display the Law of Segregation at work. This is of course all based on the fact that the kernels present on our piece of corn featured a rather dominant trait, and seemingly follows the Mendelian laws.

Materials and Methods

In this lab, we were given a single ear of corn (already de-husked) along with an image of a set of mung bean seedlings. I initiated this lab by meticulously counting the mung bean seedlings, tallying up the green, albino, and missing seedlings to create a table of data. Upon concluding this task, I counted every individual kernel on the ear of corn in order to record accurate information regarding the four genotypes present. Once each kernel was tallied I built a Chi-Squared test in order to calculate the recorded data. It is worth noting that the experiment focused on a 9:3:3:1 ratio. The following equation is how we calculated the Chi-Squared test: In Stallsmith’s Lab Manual, it is stated that d is the deviation for each test class, and that e is the predicted value for each test class (Stallsmith, 2017). Finally, when this is all calculated, it is represented with a degree of freedom via the experiment. Once all is said and done, deviation will either be determined to be significant or insignificant.

Results

I will start sharing my results by first presenting my tables. The data in Table 1 uses information provided by our Lab Instructor and was used in order to provide an accurate ratio as opposed to one that might potentially be incorrect. The ratio represented allowed for an easier calculation for the Chi-Squared value. Thankfully, with each group having a unique ear of corn, I did not need to worry as much about the calculation being similar to the other groups (the image of seedlings yielded inaccuracies amongst each group). After meticulously counting I was able to come up with the information found in Table 2, which gives insight to how many of each type of kernel was present on my ear of corn, along with lists of the Genotype(s) that each type carried.

Discussion

The overall result of this experiment showed that the Chi-Squared values can be calculated rather easily and efficiently, and that deviation can certainly occur for the more insignificant values. Because of these insignificant values, the Law of Inheritance has been proven. On top of this, the ear of corn my group was provided featured a ratio that followed a ratio similar to the typical 9:3:3:1 ratio. This factor shows that this experiment provided us with an example of the Law of Segregation. I feel that the best way to improve upon this experiment would be to bring new ears of corn into the lab as opposed to older ones, as the ones we were provided with had a rather significant number of kernels missing, which while it made the experience a bit shorter than it could have been, we have no real way of telling how many of each kernel is missing so our overall numbers could have been incorrect. As for importance, this lab is very important, as it provides us with examples of Mendelian laws and how they can be represented. As for the purpose of this study, the idea is “to evaluate a positive finding from a previous study, to provide credibility that the initial finding is valid. Replication is essential for establishing the credibility of genotype-phenotype association…”. Essentially, these laws have been proven consistently over a long period of time through various (yet similar) experiments, adding credibility to it all.