Drafts

The DNA is the foundation of variability. The different arrangements of four nitrogenous bases, thymine, adenine, guanine and cytosine, determine how cells function and what characteristics an orgamism possesses. An organism's genome contains millions of bases which code for proteins with a variety of functions. With a possible bases comes a million possible errors. Each base in the genome has a probability of being switched out for the wrong base due to mutations from UV radiation, errors during DNA replication and even mutagenic substances. Mutations that arise from changing single bases are called point mutations and these account for numerous genetic disorders muscular dystrophy, sickle-cell anemia, phenylketonuria etc. With the advent of CRISPR-Cas9 system, it is posisble to create double-stranded breaks that allow the integration of random sequences. This is useful in research settings where knockout mutations are the aim but for therapy, the traditional CRISPR/Cas9 machinery may only aggravate the disease. The need to change single nucleotides spurred the discovery of base editors. Base editors consist of inactive Cas9 scissors paired with a protein that catalyzes the desired base change. In order to circumvent potential revertion to the incorrect base by the cell's proof-reading machinery, the base editor creates a nick in the other strand of DNA. This marks that strand for correction, allowing the proof-reading machinery to integrate the correct complementary base. 

          The first study of what would come to be called aDNA was conducted in 1984, when Russ Higuchi and colleagues at the University of California, Berkeley reported that traces of DNA from a museum specimen of the Quagga not only remained in the specimen over 150 years after the death of the individual, but could be extracted and sequenced. To determine whether DNA survives and can be recovered from the remains of extinct creatures, they examined dried muscle from a museum specimen of the quagga, a zebra-like species endemic to South Africa that went extinct in 1883. Over the next two years, through investigations into natural and artificially mummified specimens, researchers confirmed that this phenomenon was not limited to relatively recent museum specimens but could apparently be replicated in a range of mummified human samples that dated as far back as several thousand years.

The second experiment was carried out to examine the mesophyll conductance responding to ABA application (Mizokami et al., 2017). This experiment was done in a similar setting to the first experiment with the investigation of the change in the CO2 levels. Mizokami et al. grew each plant, Col-0, ost1, and slac1-2 in a pot that were placed in a chamber that provided a photoperiod of eight hours, 23 degrees Celsius for day temperature, 21 degrees Celsius for night temperature, humidity of 60%, ambient CO2  of 390μmol and a Hoagland solution twice a week (Mizokami et al., 2017). In this ABA application experiment, the CO2 level in the chamber was not manipulated and stayed constant for two weeks. Mizokami et al. first made a tiny slit with a razor in the Arabidopsis thaliana’s petiole to make a space to inject the ABA solution so that the plants will not wilt (2017). They kept these plants in the dark for about 15 minutes before turning on the fluorescent lamp again to prevent the slit from embolism. After the plant is adjusted to the slit, an artificial xylem sap called AXS was injected and the fluorescent lamp in the chamber was turned on shining a 600μmol light on the plants. Then the initial photosynthetic rate was measured (Mizokami et al., 2017). When the initial photosynthetic rate and the atmospheric conditions were recorded, Mizokami et al. applied 100μl of ABA solution gradually into the same slit where they injected the AXS solution (2017). It took an hour and a half to complete this injection, and they measured the photosynthetic gas exchange parameter to compare the results from the initial data. Not only the measurements, but also ABA contents in the leaf was observed (Mizokami et al., 2017). By using liquid nitrogen to freeze the leaf and removing the veins from it, the contents were determined by using a liquid chromatograph and a mass spectrometer. Finally, to evaluate the mesophyll conductance, Mizokami et al. created an equation (Figure 1) to analyze how sensitive the mesophyll is to both ABA and CO2 levels (2017).

Fragile X Syndrome is a dominant X- linked syndrome, meaning it affects both men and women. Since men only have one x chrolmosome, it effects them more frequently and with more severity. With inheritance, the father passes on Fragile X only to the daughters since any sons will recieve a Y chromosome from him. If the mother has Fragile X or acts as a carrier for it, there is a 50% chance her children will be affected by it.

The Fragile X mutation was discovered in 1943 by two scientists, Bell and Martin. The disease was originally named after them, but then renamed after it was found to a sex-linked condition with a "fragile" site on the X chromorosome. The mutation that causes fragile X is a CGG repeat on the X that repeats more than normal. Normally, it repeats between 6 and 55 times. Anything over 55 repeats is considered fragile x.

About 50% f women with fragile x do not show any symptoms (long face, large ears, and flat feet). Also men and women who have between 55 and 200 CGG repeats have what is called "pre-mutation" fragile x. Pre mutation is incomplete fragile x but can cause multiple issues like ovarian failure and tremor ataxia syndrome. If someone has 200 or more CGG repeats, they have complete fragile x. The greater the number of repeats, the greater the severity of the effects. Those with fragile all show a silenced FMR1 gene with no FMRP proteins. 

Sharks and some other marine organisms are able to use electric signals to their advantage. Some organisms can emit electrical signals while others are highly sensitive to electrical signals. Sharks specifically are highly sensitive to electrical signals that can be used for communication and detection of the environment. Organisms that emit electrical signals can use their abilities for defense or killing prey as well. There are two main types of electrical receptors. The first being tuberous receptors which are found only in electric fish and respond to the high frequency discharge rates. The other type of electrical receptors is ampullary receptors. These receptors are found in both electric and non-electric fish and respond to much lower frequencies.

Organisms use vibration and sound perception sensory systems to help them respond to their environment. Snakes posses two sensory systems to respond to both airborne and substrate vibrations. Squid and Cuttlefish have a line of ciliated cells on their heads and tentacles that area analogues of lateral lines in fish. Water striders use water disturbance for sex determination. Males and females have different wave signals that they create. Pit vipers have pit organ neurons that overlap in their brain with visual neurons. This produces an infrared vision that allows them to detect prey.

Organisms have different specialized sensory systems. Many organisms are highly sensitive to small amounts of chemical substances. Many fish are highly sensitive to amino acids found in many marine mammals. Many fish are highly sensitive to amino acids. Taste buds are another sensory system that organisms have. Catfish have taste buds throughout their body and are essentially open pores with microvilli for increased surface area. Insects are hypothesized to have five different sensory neurons, each with a different purpose.

In bacteria, transcription, and translation take place simultaneously. In eukaryotes, transcription takes place in the nucleus, and the pre-mRNAs then undergo processing before being moved to the cytoplasm for translation, which allows opportunities for gene control after transcription. Consequently, posttranscriptional gene regulation assumes an important role in eukaryotic cells. RNA processing and degradation is a common level of gene regulation in eukaryotes.

A mixture of ground nutmeg (1.00 g) and tert-butyl methyl ether (3.0 mL) was added to a round-bottomed flask and gently boiled for ten minutes. After settling, the resulting liquid was cotton-filtered through a pipet, rinsed again with tert-butyl methyl ether (2.0 mL), and filtered as before into a tared 25 mL Erlenmeyer flask. The filtered solution was then evaporated gently to yield the crude product (0.763 g, 1.05 mmol, 76.3% recovery), which was subsequently recrystallized in acetone (15.26 mL) to yield a once-recrystallized product (0.147 g, 0.203 mmol, 19.3% recovery), isolated via vacuum filtration. Hydrolysis was performed in a clean round-bottomed flask through reflux of a solution of the trimyristin (0.060 g, 0.083 mmol), 6 M sodium hydroxide (2.0 mL), and ethanol (95%, 2.0 mL) gently for 45 minutes. The resulting contents of the flask were then poured into a 50 mL beaker containing 8 mL of water and concentrated hydrochloric acid (2.0 mL) was added dropwise while stirring. The beaker was then cooled in ice water for ten minutes while stirring, and vacuum filtration was used to collect the resulting myristic acid product (0.046 g, 0.201 mmol, 82.14% yield). During the hydrolysis portion of the experiment, the remaining trimyristin (0.086 g, 0.12 mmol) was recrystallized a second time to obtain a twice-recrystallized product (0.067 g, 0.093 mmol, 77.9% recovery), which was subsequently vacuum filtrated. The melting points of the once-recrystallized product (55 - 57 ℃), product of hydrolysis (54 - 55 ℃), and twice-recrystallized product (54 - 56 ℃) were then taken.