Essay on Examining the Crosses Between Drosophila Fruit Flies

A) Their F1 offspring were 97 wild type quahaug flies. What is the genotype of these F1 flies??

The parents are both homozygous. The homozygous dominant would represent the wild type. And the homozygous recessive would represent the other fly parent of a different strain. The F1 generation would consist of 100% Wild Type but they would all be heterozygous in carrying the recessive gene.

It was decided that there would be 80 vestigial flies and 20 wild type flies to total to an initial population of 100 drosophila. Next, the flies were anesthetized flies using Fly Nap. The flies were counted out to reach desired ratio, sexing the flies making sure there are equal amounts of males and females to be sure there is ample individuals to allow successful mating. The fly’s food was prepared by taking a frozen rotten banana, cutting it in half, mashing up the banana meat, and mixing yeast into it. The

Introduction: The intention of this lab was to gain a better understanding of Mendelian genetics and inheritance patterns of the drosophila fruit fly. This was tasked through inspecting phenotypes present in the dihybrid crosses performed on the flies. An experimental virtual fly lab assignment was also used to analyze the inheritance patterns. Specifically, the purpose of our drosophila crosses is to establish which phenotypes are dominant/recessive, if the traits are inherited through autosome or sex chromosomes and whether independent assortment or linkage is responsible for the expressed traits.

The motivation of this lab report is to use Mendel’s Laws of Inheritance to analyze and predict the genotypes and phenotypes of an offspring generation (F2) after knowing the genotypes and phenotypes of the parent generation (F1). The hypothesis for this experiment is that the mode of inheritance for the shaven bristle allele in flies is autosomal recessive in both male and female flies.

It would be expected that the mutant F1 flies would be heterozygous for the allele responsible for the grounded trait. If two F1 flies were mated, the percentage of flies that would be expected to be wildtype in the F2 generation would be 25% mutants given that the mutant allele (ap) is predicted to be recessive and, leaving 75% to be wildtype (ap+).

11. The progeny of a Drosophila female (heterozygous at three loci: y, ct, and w) crossed to a wild type male are listed below:

The next row(F2 generation), shows us the offspring numbers of a male and female from the F1 generation. Those numbers give us a ratio of 1:1:1:1 of 1 wild male to 1 yellow male to 1 female wild to 1 female yellow. This tells us that there is around the same amount offspring for of each type of fly in the F2 generation.

METHODS: In this experiment, the instructor provided us with 30 ebony individuals and 20 wild type individuals. In order to get an exact amount of each type, we anesthetized the flies and counted them off by gently using a fine point paint brush. Then all 50 Drosophila were put into a population cage which had a lid that had six holes for the centrifuge tubes. Two food tubes and four clean, empty tubes were added on the first day. Each food tube consisted of half a cup full of food mixed with 6-7 milliliters of water. This was the fly medium. The food should turn blue once the water is added. Each tube was labeled with a number and with the date. Every two to three days we added one more food tube until all 6 tubes contained the fly medium. After all 6 tubes were filled, the following days after we exchanged the first food tube with a new food tube. At the end of the experiment, we fed the flies with a total of 8 food tubes. Then the flies were anesthetized, again. At the end of this four week lab, the number of living ebony and wild

Introduction Gregor Mendel, the father of genetics, established the basic principles of heredity by crossing different varieties of pea plants and observing the succession of traits in the resulting generations. In order to studying the trends of heredity, model organisms are crossed and observed for the resulting traits. Drosophilia melanogaster, the fruit fly, has been a useful species in the study and practice of genetics. The fruit fly is an excellent model organism due to its short generation time, large offspring numbers, simply and cheap care, easy handling in a lab setting, and large and varied stocks available with minimum cost. It was among the first organisms to be used for genetic analysis (Pierce, 2005).

we said goodbye and placed them in the fly morgue. We allowed the F2 larval

The Drosophila melanogaster is one of genetics most studied organisms. This is due to the Drosophila melanogaster being an excellent model organism. The Drosophila melanogaster has a short lifespan and is genetically similar to humans (Adams 2000). This experiment had three major goals. The first goal of this experiment was to determine which eye colors, body colors and wing type are dominant or recessive. The second goal was to determine if the gene for eye colors, body colors and wing type are on an autosomal or a sex chromosome. The third goal was to determine if eye colors, body colors and wing type are physically linked or independently assorting (Morris and Cahoon). First

This wings clipped strain will provide the transposase enzyme, allowing the P-element to be mobilized, and provides a dominant marker (stubble), allowing us to recognize flies in which the P-element could have been mobilized. We are hoping that, because the P-element is so close to the DMAP1 gene, that mobilization will cause the P-element to insert into the DMAP1 gene. Although P-elements can insert anywhere onto the genome, they tend to insert into the beginning of genes, and because DMAP1 is so close to where the P-element has inserted, it is likely that it will insert into DMAP1 when mobilized. The P-element could insert anywhere on chromosome 2, as well as anywhere else in the genome. After mobilization, it is possible that chromosome 2 will no longer have the insert, or could have multiple inserts at different locations. If the P-element does insert into the DMAP1 gene, it would deactivate it, as its DNA “code” would no longer be correct, and it would not produce a functional protein if transcribed. As there is no guarantee that the P-element will insert into DMAP1, we will do multiple crosses. The mobilization cross will involve flies of genotype Xyw/Y;P*/P*;+/+ crossed to Xw/Xw;Sp1/CyO;Sb Δ2.3/TM6B. We will then collect progeny of genotype Xw/Y ; P*/CyO; Sb Δ2.3/+, which will be recognizable by their curly wings and stubble. The presence of the stubble phenotype tells us that the wings-clipped transposase element was present to allow the P-element to mobilize. When the P-element is mobilized, it may move in each individual cell that will form sperm at the end of meiosis. For this reason we will collect males individually in preparation for the next cross, as each male could have the P-element inserted into a different position. We will then take each male

First step, one of the major issues was that all members in the group did not pay attention to the gender of flies in each vial of the unknown P cross of the F1 generation. The number of male and female might not equal to ratio 1:1 in each vial which led to have an error because Bar eye mutation is a dominant X- linked gene that does not assort independently while vestigial wing mutation is autosomal mutation located on chromosome number 2. As a result, vestigial gene assorts independently and does not play significant role with gender in the next generation: however, gender played significant role when determining mutation specifically for Bar eye mutation. Second, there was no differences in the traits as flies observed in first count on April 10 and second count on April 17. Third, there was a difficulty while transferring flies from the vails to the nap chamber. Flies in some vials remained sticking in the food gel due to knocking issue. Some vials accidently knocking aggressively made the flies stick in the food gel. Also, some fruit flies flied and some of them killed accidently while putting the stopper because transferring the flies were quickly from the vials to the nap chamber. Growth condition were not good for some vials that made the group to discard some vials and used the backup vials due to contamination and bacterial infection that killed the flies in some vials. Finally, according to table 4, the individual Chi square for vial A, C, and D was lower than the critical value and support the hypothesis; however, Vial E showed Chi square value greater than the critical value which rejected the hypothesis. Vial E during the second count was not knocked to get the flies away from the stopper which made some of them to fly while transferring them to the nap

For our first generation (F1) of flies we chose to cross apterous (+) females and white-eye (w) males. We predicted that the mutation would be sex linked recessive. So if the female was the sex with the mutation then all females would be wild type heterozygous. Heterozygous is a term used when the two genes for a trait are opposite. The males would all be white eye since they only have one X chromosome. If the males were the sex that had the mutation then all the flies would be wild type but the females would be heterozygous.