Drosophila Genetics Lab Report

Throughout this experiment a number of random and procedural errors were apparent; these errors could have affected the results of the experiment in a number of ways. One experimental error that occurred during the experiment was that some flies became stuck in the food source and died. The main cause of this was the fact that the fly vials were stood up (vertically) before the flies had fully recovered from the anaesthetic. This could be overcome in future experiments by ensuring that the vials are kept horizontal until all of the flies fully recover from the anaesthetic.

---If given traits and parents, be able to use a Punnett square or patterns to predict the probability of offspring for a given cross and express it as a fraction, percent, or ratio.---

Once the Punnett square for Question 12 is complete, calculate the ratio of purple and yellow kernels (recall that if the dominant trait is present, it will be expressed).

This Punnet Square represents the F1 offspring breeding with each other to create more offspring. This second set of offspring is the F2 generation. If both parents are heterozygous dominant, then the offspring expected would be: 50% heterozygous dominant, 25% homozygous dominant and 25% homozygous recessive.

Calculate the ratios of the genotypes and phenotypes of the offspring in the F1 generation.

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.

You can collect individual flies that you have generated (for use in future experiments) by dragging them

This lab had 2 exercises. Exercise 9.1 involved observing pictures of 60 F2 offspring and recording the phenotypes for 6 different traits. Exercise 9.2 required us to perform the “chi-square test” to determine whether the data we collected matches the standard Mendelian ratio.

Flies may escape vials during experiment. Due to their small size, they should not cause significant harm if accidentally swallowed. Precaution should be taken to reduce likelihood of impacting the local ecosystem if significant amounts of flies are

9. Fourth week: Begin removing the F2 flies. Record their sex and the presence or absence of mutation(s). The more F2 flies collected, the more reliable the data will be. You may have to collect flies over a three-or four day period (or more). Try to collect at least 200 flies (probably quite a bit lofty).

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

Using the Hardy-Weinberg equation, calculate the predicted genotype frequencies for each population scenario below. Place your calculations and data in the space provided below. Once you have calculated the frequencies, answer the conclusion questions for each one. Please remember that all calculations must be shown for full credit.

Some larva containing vials had hatched into flies. Counting of the flies began at this point. As flies started to grow, at different rates for each vial, with in the first seven days after all larva had hatched the flies were counted. The procedure was done according to theDrosophila manual (45-2620)

This experiment looks at the relationship between genes, generations of a population and if genes are carried from one generation to another. By studying Drosophila melanogaster, starting with a parent group we crossed a variety of flies and observe the characteristics of the F1 generation. We then concluded that sex-linked genes and autosomal genes could indeed be traced through from the parent generation to the F1 generation.

This table helps show all the possible genotypes from one set of parents. The table shows that the genotypes purple and starchy are dominant, and the genotypes yellow and sweet are recessive.(stallsmith)