Phenylthiocarbamide Lab Report

L.H Snyder states that if PTC bitterness taste is inherited, if it would be safe to for it to be referred as a Mendelian

PCR permits the synthesis of millions of copies of a specific nucleotide sequence in a few hours. It can amplify the sequence, even when the targeted sequence makes up less than one part in a million of the total initial sample. Steps of the PCR cycle are shown in below figure.

Receptor proteins recognize bitter-tasting compounds on the surface of taste cells. There are approximately 30 genes for different bitter taste receptors. The gene for the PTC taste receptor, TAS2R38, was identified in 2003. Sequencing identified three nucleotide positions that vary within the human population (Kim et al.); each variable position is termed a single nucleotide polymorphism (SNP). One specific combination of the three SNPs, termed a haplotype, correlates most strongly with tasting ability. In this lab, non-tasters (homozygous recessive, tt) can determine their genotype without having to run the PCR and electrophoresis because non-taster gene is recessive. Thus, the only way for them to express recessive phenotype is to have the tt alleles of

That number, or rather percentage, of children that can or can not taste PTC correlates with their parent’s results. In case where both parents can taste- most of the kids also can taste, percentage of kids which can taste is lower in a combination where one parent can taste and other cannot and if parents cannot taste it then there is no way that children can taste it.

PTC stands for Phenylthiocarbamide. I place it on my tongue to taste it and the taste was disgusting and bitter on my tongue. And I turn to see my classmate and he didn’t taste the bitterness but my other classmates reacted the same way I did. Later on, we’ve learned that whoever who reacted like me after tasting the PTC taster have more taste buds than people who reacted like my classmate where they can’t taste the bitterness from the taster. This shows an example of how people taste the food, liquid or a taster differently. Since people who have a lot of taste buds can catch more flavors than a person who has a few taste buds on their tongue. I think this can do on how people eat on a daily basis. Like for me, I eat food ranging from sour to spicy and it explains why I could taste bitterness on the PTC taster. But, it’s normal to react that way since it was supposed to taste

PCR works by denaturing the double-stranded DNA and annealing the primers to the newly-made single-stranded DNA, leading to the extension/elongation of the DNA by a polymerase that attaches to the primer/DNA strand. The PCR reaction strums through a handful of temperature cycles to maximize each step and the amount of product.

A type of next-generation sequencing is illumina sequencing. Illumina sequencing sequences large amounts of DNA in a single attempt. In this process, the sample is firstly cleaved into short fragments. Then, PCR is performed in order for amplification of each read to be carried out. This would subsequently lead to the creation of numerous copies of the same read, at a particular location. Then, separation into single strands occurs, so that sequencing can be performed. This process is followed by the introduction of fluorescently labeled nucleotides and DNA polymerase into the slide, with a termination so that one base is added each time. Therefore, at each read location, a fluorescent signal would be present to indicate the addition of a base. Then, another cycle is performed, with the terminators and fluorescent signals being removed so that another base can be added and to prevent the signal from interfering with future cycles. Computer technology is then utilized to detect the base at each site, so that a sequence can be constructed. This will result in sequence reads of the same length since the same number of cycles will be performed for each

The goal of this experiment was achieved because the subject’s genotype for PTC, with a phenotype of taster, was determined using PCR and gel electrophoresis. The genotype was heterozygous dominant (Tt) based on the number of DNA fragments in Figure 1. Therefore, the gel picture matched the prediction and hypothesis that either three or two fragments would be present since the subject was a taster for PTC. The DNA fragment amplified by PCR was about 300 base pairs long, 303 bp to be specific. The enzyme, Fnu4HI, cut the DNA at a restriction site 5’-GCNGC-3.’ Tasters would have a C in the amplified fragment, while non-tasters would have a T. Once the DNA was cut, the fragments created were 200 and or 100 base pairs long if the DNA was from a taster. This is what occurred for the subject as seen in

In general, could those tasting PTC also taste sodium benzoate? Is this evidence for or against your hypothesis?

This means that at some point in time, those who were able to taste the chemical phenylthiocarbamide had an advantage towards them. Fisher though that being a heterozygote PTC taster was more of an advantage rather than being homozygous for PTC tasting. Fisher believed that with time, one of the alleles would be eliminated from the population, leaving to the conclusion that the advantage of PTC taster is present. Even though till this day we do not know what that advantage is for, one hypothesis is that the PTC tasters have a genotype in its locus that influence them to select certain food types based on whether its bitter or not. Knowing that bitterness has toxic compounds involved in it, PTC tasters will avoid this food type easier than non-tasters of PTC. So although there is a variety of food out there, PTC tasters can have them on a list of presence or avoidance, unlike non-tasters that can’t do

One such situation is identifying the presence of phenylthiocarbamide (PTC), which is a bitter compound found in plants. About 70% of people are able to identify the presence of this compound, but the genetics of the ability to taste PTC illustrate a much more complex story. The different variations of the PTC taster gene exemplify human evolution

0.01 g of phenyl red was weighed out and put it in the test tube and also 1 mL of buffer was added to the test tube. It will form a yellow color as indicated it is acidic. So after the buffer run through the column and reach the surface of the column bed, we labeled 16 cuvettes and from 1-16 with 1 was used for blank.

PTC is an organosulfur chemical which stands for Phenylthiocarabamide also known as Phenylthiourea(Wallace,2013). PTC is commonly used for inhibiting melanin in zebra-fish embryos, and it is also used for growing transparent fishes(Li,2012). However it is also used as a genetic marker which is where the phenomena with PTC originates(Wooding,2013). PTC is a chemical that has a bitter taste, but not every individual has the ability to taste its bitterness because to others PTC is completely tasteless. The ability to taste phenylthiocarbamide is believed by some to be an ancestral trait from chimps where tasting a PTC compound was used to avoid toxic plants, and then over the years it evolved in humans(Bamshad,2014). Depending on the specific experiment on average 3 out of 4 people have the ability to tastePTC(Bamshad,2014).

What steps are involved in carrying out PCR and biologically, what happens during each step? Why did we use PCR? (15 pts)

The polymerase chain reaction or PCR for short can be used to create many copies of DNA. This allows the DNA to then be visualized using a dye like ethidium bromide after gel electrophoresis. The process has been refined over the years, however the basic steps are similar.