Introduction The objective of this experiment is to determine what genes are responsible for the white-eye color in two strains of Drosophila melanogaster, known as the common fruit fly. Drosophila is used as the experimental organism for many reasons which include its small size, easy maintenance, short 10 day generation time, and a fully sequenced genome. The characteristics of the wild type, which is the most common phenotype found in nature, include brick red eyes, long wings, gray/tan body, and smooth bristles. Of course, there are mutations that occur that cause specific traits to deviate from the wild-type phenotype. These traits include wing length, bristle shape, body color, and eye color. For instance, fly wings that are shorter …show more content…
The white (w) eye color gene is located on the X chromosome at 1.5 genetic map units (1). The mutation is also recessive, meaning that each fly has different copies of the gene if they are either male or female (2). In wild-type Drosophila, the brick red color is visible due to the combination of two pigments, brown and scarlet. The synthesis of drosopterin for bright red pigments is controlled by the (bw+) gene and the synthesis of ommochromes for brown pigments is controlled by the (st+) gene (7). Therefore, there are two pigment synthesis pathways that must be working in order for the flies to express the brick red eye color. In addition, transport proteins are responsible for transporting both pigments into the eye in order to express the color (8). Thus, both the pathways responsible for the synthesis of brown and red pigments must work properly as well as the genes that encode for transport proteins. Despite having white eyes, Drosophila flies with this mutation still experience normal eyesight …show more content…
In order to figure out the genes responsible, there are several other factors that must be determined. These factors include the number of genes involved, if each gene is x-linked or autosomal, if the mutant or wild-type allele for each is dominant, and if genes are linked or on different chromosomes. Proposed crosses include reciprocal crosses between the pure-breeding mutants of strains A and B with the wild-type will help determine if the genes or sex-linked or autosomal, in addition to which alleles are dominant (8). Another proposed cross includes complementation crosses between pure-breading mutants from strains A and B to determine if one or two genes are involved (8). Furthermore, testcrosses between F1 progeny and pure-breeding recessive mutants from strains A and B, which will help determine if genes are linked on the chromosome or if they assort independently (8). These proposed crosses are shown in the attached
Variation in selection pressures on the goldenrod gall fly and the competitive interactions of its natural enemies
The main purpose of this experiment is to examine the results of wild-type mutant crosses which influence the arrangements of ascospores in asci in the fungus Sordaria fimicola. These resulting arrangements help calculate the map distance between the centromere and spore color genes in Sordaria. My hypothesis was that due to so many group observations accounted in, the data will be underestimated and the results will not fit into the chi square table. A sample from Petri dish with both mutant stock cultures is observed after a week. The ascospores must appear in MII pattern 2:2:2:2 or 2:4:2 arrangements in order for the crossing-over to occur. Next, based on the data collected, the class calculated the map distance. If the map distance does not fit the value obtained by the researchers from the many successful experiment attempted, then the experiment had errors. And due to this, the class experiment cannot accept the null hypothesis according to the chi square test. However, our class experiment accepted the null hypothesis and so it was a success.
17. Fruit flies normally have eight chromosomes. The diagram below shows the result of meiosis in three fruit flies to produce gametes with the number of chromosomes indicated. The male then mates with both female A and female B to produce three zygotes (1, 2, and 3).
Test 4: All three phenotypic frequencies saw a reduction in their number as the homozygote fishes saw a reduction in their number and were not able to pass on their alleles to create either their colored fish or a heterozygote. Both yellow and blue allele frequencies decreased by the same
The idea of the project was to experiment breeding Drosophila Melanogaster (fruit fly) to figure out if certain genes of that species were sex linked or not (autosomal). A mono-hybrid cross and di-hybrid cross was performed. For the mono-hybrid cross, white eyed female and red eyed male were placed in one vial for them to reproduce. For the di-hybrid cross, red eyed and normal winged flies and sepia eyed and vestigial winged flies were placed in their vial to reproduce. In the mono-hybrid cross the results expected were within a 1:1:1:1 ratio. Expected results similar to the expected desired null hypothesis proposed with what the F1 parental generation breeds. The potential results would have had to have been within the ratios of 9:3:3:1. The results were clear and allowed the null hypothesis to be correct. The white eyed gene in the fruit flies is sex linked. Sepia eyes and vestigial wings are not sex linked and are examples of independent assortment.
Drosophila melanogaster is a model species used commonly for research in the areas of genetics and phylogeny (Kohn and Wittkopp, 2007). Drosophila is a model species due to the abundance of offspring, short generation times, and the ease of identifying wild type vs ebony phenotypes (University of South Florida, 2017, Biodiversity Lab Manual). This experiment is being performed in order to evaluate whether or not a fly culture after 3 generations will conform to the Hardy-Weinberg equilibrium equation. This equation is being used as a null hypothesis and will most likely not be achieved due to the relatively small population of flies being used in the experiment as well as other factors such as genetic drift (Dansereau, 2014). The experiment will take place over seven weeks in which the procedure will alternate between scoring the
In our genes, multiple different alleles determine whether one person will have a certain trait or not. Alleles are what make-up our genotypes and in this lab, we wanted to determine the genotypes of our class in the two loci: TAS2R38 and PV92. The TAS2R38 locus codes for a protein that involves the bitter taste of PTC; the gene determines whether or not a person will taste the PTC paper as very bitter or no taste at all. People with the “T” allele are tasters while those that are homozygous recessive (tt) are non-tasters. The taster locus can be found chromosome 7.3 The two different alleles present in the could be due to the effect of evolution and natural selection because the same can be found in chimps.4 The PV92 locus does not code for any protein but rather involves an Alu element that is 300-bp long. A person with the “+” allele would have the Alu element making that sequence longer while those with the “-“ allele don’t have the element and would have a shorter sequence. This locus can be found on chromosome 16.3 There are multiple Alu sequences found among primate genomes but there are human specific sequences such as the one found on the PV92 locus.1 In the experiment, student DNA was collected from cheek cells and PCR was used to target the loci and amplify the region of DNA. In the taster gene, after amplification, a restriction digest was performed to differentiate between the two alleles. The digest was able to show differentiation because those with the “T” allele would have two bands from gel electrophoresis and those with “t” will have one band because the restriction enzyme doesn’t cut it. For the PV92, we were able to distinguish between the alleles due to the added length of the Alu element. Those...
The major topic of this experiment was to examine two different crosses between Drosophila fruit flies and to determine how many flies of each phenotype were produced. Phenotype refers to an individual’s appearance, where as genotype refers to an individual’s genes. The basic law of genetics that was examined in this lab was formulated by a man often times called the “father of genetics,” Gregor Mendel. He determined that individuals have two alternate forms of a gene, referred to as two alleles. An individual can me homozygous dominant (two dominant alleles, AA), homozygous recessive, (two recessive alleles, aa), or heterozygous (one dominant and one recessive allele, Aa). There were tow particular crosses that took place in this experiment. The first cross-performed was Ebony Bodies versus Vestigle Wings, where Long wings are dominant over short wings and normal bodies are dominant over black bodies. The other cross that was performed was White versus Wild where red eyes in fruit flies are dominant over white eyes.
The purpose of this experiment is to conduct genetics studies using drosophila fly as the test organism. Scientists can study the basic biology that is shared by all organisms using a model organism, such as drosophila fly1. Drosophila fly, or more commonly known as fruit fly, has several qualities that makes it well suited for experimental genetics cross. First, fruit flies are low maintenance organisms. They are small in size (few millimeters long), so they occupy a small space and a lot of them can fit in one vial at the same time. They only require a media to feed on. In this lab, instant media was used, which is efficient as it only requires the addition of water to be used. This media contains ingredients that the fruit fly can feed one,
It is challenging to analyze phenotypes when there is little information known about genes. With the moths, nobody knows which of the moth's genes are responsible for the changes in color, so a genetic analysis is extremely difficult to do.
The experiment was a three week long experiment. Prior to fully engaging in the experiment, it was important to sort out the flies. In order to separate out the flies, they had to be put to sleep. The blue caps were removed first and then put to sleep. Using the Triethylamine anesthetic fly nap, the vials were placed horizontally on their side so that the side without any netting was at the top, the swab once submerged into the fly nap was then inserted into the vials containing the flies. It was important to make sure the fly nap applicator did not touch the flies and did not stay in the vial for too long because it would kill them. Once the flies were asleep, they were emptied out onto index cards with the help of a paint brush; of course
Albinism is a genetically linked disease and is presented at birth; it is characterized as a lack of pigment called melanin that normally gives color to a person’s skin, hair and eyes. This results in milky white hair and skin, and blue- gray eyes. Melanin is synthesized from amino acid called tyrosine, which originates from the enzyme tyrosinase. Albinism affects all races and both sexes; people with this disease have inherited a recessive, nonfunctional tyrosinase allele from both parents (Saladin 189). The inheritance of Albinism is coded in the gene of the parent’s alleles. Alleles are two different versions of the same gene or trait and are found on the same place of a chromosome. One allele is coded for the production of melanin that will produce normal skin, hair and eye color and another allele that represent the lack of melanin that produces abnormal skin, hair and eyes.
Q: 18. Do you think the mutated Fire allele fb is dominant or recessive to the existing Fire alleles F?
The main purpose of this lab was to determine if the mutant genes were dominant or recessive, autosomal or x-linked, and if either gene combination was linked. Also, if they were linked, one was to determine how far apart. In this experiment, fruit flies were used to obtain a better understanding of Gregor Mendel’s genetic principles. Using the law of segregation and the law of independent assortment, one of the main objectives was to learn how certain traits were inherited while others were not and to determine if two different fruit fly crosses fit the 9:3:3:1 ratio. In the beginning of the experiment, a two vials were obtained and prepared, and following this the phenotypes and sexes were observed. In each vial, there was a cross with first
The results of the fruit fly (Drosphila melanogaster) experiment undertaken are important for numerous reasons. Firstly, the results obtained give statistical insight into what the data values are showcasing in this experiment. The outcomes being depicted from a mathematical point of view makes it easier to comprehend. This laboratory activity demonstrates how count data gives a much better understanding of statistics (especially for genetics and evolution). It is better to obtain results from appropriate statistics rather than making conclusions based on data such as random sexual relations, genetic and evolutionary change and diversity of the fruit fly species. Secondly, the results summarize the data into an interpretation that is to the