Through group member was not able to

Through gel electrophoresis and evaluating the location and number of bands, the intention of the lab was to determine if the genotype, after the isolation of the DNA fragments, matched the phenotype of the intensity of the bitter taste as oppose to those without the taste of the Phenylthiocarbamide, or PTC. With the utilization of the Hardy-Weinberg Principle and Mendelian inheritance, to comprehend the how genes relate to the PTC tasting, the class results were applied.         With the use of the PTC tasting test strips, the phenotypes of each group in the lab section were established. For Group Five, three out of the four group members tasted the bitterness strongly meaning that the homozygous dominant genotype of “TT” was present (Table 1). However, the fourth group member was not able to taste anything which means that that group member has the homozygous recessive genotype, “tt”. Based on the data collected from Group Five, the greatest allele frequency was determined to be the T allele. According to the data gathered for Lab Section 069, the T allele frequency was greater than that of t allele frequency (Table 2). As reported by the calculation of the allele frequency based on Figure 2, the T allele frequency was greater than the t allele frequency. The T allele frequency had a percentage of 52.5% while the t allele frequency had the percentage of 47.5%. This information was also demonstrated in the class data, (Figure 3), in which the T allele frequency is greater than the t allele frequency. In accordance with the data of the class, the frequency of the t allele was greater than the frequency of the T allele in which the t allele had the percentage of 58.6% while the percentage of the T allele was 41.4%. To calculate the expected frequency of the genotypes, it was necessary to work with the allele frequencies and the frequencies of the initial observed genotype. The frequencies of the initial observed genotype were made up of the single group of four, the lab section, and the entire class. To obtain the initial observed genotype, the ratio of individuals with a genotype to the total number of individuals was taken. As the frequency of the T allele was noted as having the greater frequency than the t allele, the Hardy-Weinberg Equation (p^2+2pq+q^2=1) was tested to discovered that the heterozygous genotype was the most common. With background information of the Mendelian genetic predictions, the idea that the frequency of heterozygotes was proven to be right. Although the TT expected genotype fluctuated throughout each sample size, the tt expected genotype was steady in being the less common genotype.         The objective of this experiment was to discover if the population was evolving. To figure out if the population was evolving or not, the Chi-Square values of the population were calculated. To determine if a population is in Hardy-Weinberg Equilibrium, the Chi-Squared values were tested to determine if the values were critical. With p-value of 0.05 and a degree of freedom of 1, the critical number came out to be 3.481. For the lab section (069), the Chi-Squared value came out to be 0.00087. As this value is extremely lower, it is concluded the numbers calculated were the results of chance. The population would have been in Hardy-Weinberg Equilibrium as a result of the null hypothesis being accepted. However, the value calculated for the entire class came out to be 10.037, being significantly greater than the critical number. It is concluded that the population is/is not at Hardy-Weinberg Equilibrium. This means that the population is in fact evolving, thus rejecting the null hypothesis. The confusion of knowing what the strength of the bitterness may have had an effect on the experiment as one may confuse a “strong” bitter taste to a “mild” bitter taste. Repeating the experiment and having a larger sample is more dependable than only doing the experiment once for a group of four. The rejection of the null hypothesis has supported our hypothesis. Natural selection is the mechanism of evolution in which some traits are more favorable than others resulting in the reproduction and survival of a species. Due to the survival and the reproduction, traits are able to be passed onto offsprings as a result of species becoming adapted to their environment. Species inherits these traits so that possibility to survive is increased. For humans, the presence of the TAS2R38 gene, a PTC taste receptor that consists of three single nucleotide polymorphisms, aides human to recognize the bitter taste (Sagong et al. 2014). The benefit of having this gene for humans is increase of survival chance because of the ability to detect harmful substances (Wooding et al. 2004). Non-tasters, tt, and mild tasters, Tt, are more likely to be selected. Those with the TAS2R38 gene, strong tasters with the genotype of TT,  are more exposed to bitter things such as alcohol, coffee, etc thus making it less favorable than those with the sensitivity to bitterness. Based on the Mendelian principle, heterozygous alleles and homozygous recessive alleles are becoming more common.

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