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
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 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.
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 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.
Q: 18. Do you think the mutated Fire allele fb is dominant or recessive to the existing Fire alleles F?
Drosophila is a small fruit fly, it is about 3mm long. This insect is a model organism most commonly used in developmental biology and genetics. The Drosophila fruit flies are especially suited in experiments because of their short life cycle which consist of two weeks; they easily reproduce many offspring, and are also cheap1. The drosophila contains four chromosomes that can easily be experimented on, which allows in-depth observation. In this experiment, Drosophila melanogaster were used to identify the properties of Mendelian inheritance. The Law of Segregation states that allele pairs separate during gamete formation and randomly unite during fertilization and is carried by every individual. The Law of Independent Assortment states that each parent randomly passes on alleles to their offspring. Although, the Law of Independent assortment does not take in account the patters of sex-linked inheritance.
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.
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
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).
Drosophila melanogaster, commonly known as fruit fly, is mainly used as a human disease model organism for genetic analysis. It was during the 20th century that D. melanogaster was considered as the most significant model organism. D. melanogaster is small in size, and it has a short life span with a good reproduction rate, perfect for raising in large number and generation counts for genetics experiments. Additionally, it has a small genome which makes it easier for geneticists to keep track of changes in molecular level. Geneticists were able to uncover many human genetic diseases through the homologous genome of human and fruit flies. It started out with a small group of people led by Thomas Hunt Morgan at Columbia University. Many principles and rules of transmission genetics that are still being used in the generation of today were established in the laboratory of Dr. Morgan. Many animal models were being used before fruit flies. Using the whole-animal as a model set limitations to the types and amounts of experiments can be conducted. The use of Drosophila was able to led geneticists to overcome these limitations with tremendous promises in finding greater quality results. It was Frank Lutz, who wrote many papers on Drosophila, which introduced Drosophila to Dr. Morgan. Many experimental works on plants and animals were carried out on Drosophila instead. Through Drosophila, the discovery of mutation, recombination, relocation of chromosome, and many others were made possible. The cinnabar, cn, gene encodes an enzyme essential in the eye color formation of drosophila. It codes for the enzyme, kynurenine-3-monooxygenase, that is essential in the biological pathway of ommochrome for the brown pi...
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
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
When the F1 generation are heterozygous for each trait, the known outcome of the monohybrid cross for the F2 is a 1:2:1 genotypic ratio, which represents the heterozygous and homozygous (dominant and recessive) alleles, and a 3:1 phenotypic ratio where the dominant trait is present three times as much as the recessive