Drafts

Food color preference of avian foragers has not been widely studied.  In North America, the most common fruit color of bird-dispersed plants are red and black.  Other preferential fruit colors include blue and purple, while orange and green are rarely chosen (Janson 1983).  Fruit colors are commonly considered to increase the conspicuousness of ripe fruit in order to attract birds to disperse the enclosed seeds.  The preference of fruit color in avian foragers may be due to a variety of factors including background color, the prevalence of one color, and nutritional value associated with certain colors.  In our study, we would examine food color preferences of bird species in areas of the Amazon rainforest that are in need of ecological restoration. Frugivorous birds may play an important role in the restoration process due to their efficiency in seed dispersal (Gagetti, B L, et al, 1996).  We hope to direct the selection of plants that produce certain fruit colors to aid in the restoration of degraded forests

The name Snanker is a playful combination of the words snake and bank that McKenzie came up with during her trip and that the scientists decided to keep. After closer investigation, evolutionist Dr. Devon Elop, Dev for short, has come to the conclusion that the Magnacide dynaphyll is a close relative of Panthera onca, or the jaguar (Sartore). “Both species are well adapted for swimming and aquatic environments, but the Snanker is even more so.” While both the jaguar and the Snanker can become prey to the anaconda, the Snanker is far more equipped in dealing with the snake. The Snanker almost solely hunts anacondas and is extremely specialized in doing so. The anaconda is its only predator and due to the fact that they are larger and swifter than jaguars, they are thought to be on the way to overpopulating the species. “I’m extremely proud of this discovery,” McKenzie gloats. “I cannot wait to see what the world has to say about the Snanker”.

For the tetrad dissection crosses, since it is now known that HB1 and HA2 complement each other, their genotypes were able to be figured out at (ade1-/ade2+) for HB1 and (ade1+/ade2-) for HA2. Knowing this information, the parental ditypes (PD) can be determined as (ade1-/ade2+) and (ade1+/ade2-). This means that the non-parental ditypes (NPD) are (ade1+/ade2+) (ade1-/ade2-) and the tetratypes (TT) are (ade1+/ade2-), (ade1-/ade2+), (ade1+/ade2+), and (ade1-/ade2-). 

Once the two adenine deficient plates were incubated for a week, the results were observed. For the first plate, it was found that HA0 could grow without adenine present, while HA1, HA2, and HB1 could not. For the second plate, it was found that HB1xHA0 and HB1xHA2 could grow without adenine present, while HB1xHA1 and HA1xHA2 could not. 

Two adenine deficient plates were then divided into four sections each. The first plate was labeled with HA0, HA1, HA2, and HB1, and had each quadrant’s corresponding yeast type lightly spread onto it. The second plate was labeled with HB1xHA0, HB1xHA1, HA1xHA2, and HB1xHA2, and had each quadrant’s corresponding yeast cross from the incubated plate lightly spread onto it. For the spreading process, a clean toothpick was used to drag a small amount of the required yeast in a straight line near the edge of the plate. Then a new toothpick was used to drag a single line up from the first line of yeast cells and then spread them in a zig zag fashion. The goal of this process was to spread the yeast cells to roughly one cell thickness. The two adenine deficient agar plates were then left to incubate at 30oC for a week.

Tetrad analysis is also a valuable tool in determining the genotypes of certain phenotypes, as well as linkage between two genes. If linkage is occurring between genes then the NPD is very rare to see compared to the PD and TT. If linkage is not occurring then the ratios of PD:NPD:TT are roughly 1:1:4. Once linkage has been determined and the ratios have been confirmed, it is easy to determine which phenotype is PD, NPD, or TT and simply match it to the correct genotype. 

Mutations can be located at several different locations on a gene. Despite being able to be located at several different points on a gene, different mutations can lead to the same phenotype. Sometimes mutations occur at the same location of a gene, so when two organisms with the same mutation mate the mutation persists to the next generation. Sometimes two organisms will display the same mutated phenotype but will have mutations at different locations from one another. When mated together, the offspring of these two organisms will no longer display the mutated phenotype, resulting in a process called complementation. 

Mutations can occur at several locations on a gene yet result in the same phenotype. Yeast are a good organism to study the heritability of mutations because of their small size, easy and quick growth, and easily definable phenotypes. These factors also make yeast good for using tetrad analysis to determine genotypes. To study this, several crosses were carried out on adenine deficient agar plates to see what haploid gametes and what diploid cells could survive without adenine present. It was found that HA0 is the only haploid yeast cell that can grow without adenine, while HA1, HA2, and HB1 cannot grow without adenine. HB1xHA0 and HB1xHA2 were able to grow without adenine present, while HB1xHA1 and HA1xHA2 were unable to grow without adenine present. These results occurred because of the locations of the mutations on the gene, resulting in dominant alleles, mutation matches, complementation, and non-mating. A tetrad analysis was then taken of HB1xHA2. The results of the analysis show that there is a roughly 1PD:4TT, with three unknown tetrads due to culture deaths. While the analysis showed the correct ratio of PD:TT, it cannot be confirmed if the genes are linked or not due to the undefined tetrads. 

Yeast were plated and each plate was mutagenized by Dr. Loomis by exposing the plate to UV radiation for 9 seconds via a UV light box. Cells that turned red were allowed to grow into larger colonies to be used for the experiment. Four different mutant strains were produced, two of mating type A and two of mating type alpha. Yeast labelled “A” are of the A mating type, while yeast labelled “B” are of the alpha mating type. A YED plate was set up in a grid to perform crosses (Figure 2). Each side consisted of one mating type of non-mutant yeast (HA0/HB0), a known Ade1 mutant (HA1/HB1), a known Ade2 mutant (HA2/HB2), and the two mutant strains for that mating type (MA1/2, MB1/2). After one day of growth, the yeast were crossed gridwise. Two days later, the yeast were replica plated to an MV plate and an MV+Adenine plate (Figure 3). After three additional days of incubation, the yeast colonies were observed. The full procedures followed for all steps can be found on Moodle.

Interestingly, a plant that was exposed to white light and ethylene for two days and then grew in darkness for two days. In the case of this plant, its roots initially grew downwards for the first two days, and then they grew upwards for the next two days, giving the roots a kinked shape by the end of the four days. Similar to that, a plant grown in darkness for two days and then white light for two days grew upwards for the first two days and downwards for the final two days. This created a kinked shape in the roots, however it was in the opposite direction. Upon researching the effects of gravity on the growth of the roots, they found that gravity affected the root growth in a less impactful way.