Genetics of Organisms Essay
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Link for flylab: You will be using a sample subscription, so once you sign up you will only have access for 24 hours. It is important to do all the pre-work before logging in to get your experimental numbers. Click on the fly lab button. After reading through the lab and understanding what you will be doing, click on start lab. Introduction
FlyLab will allow you to play the role of a research geneticist. You will use FlyLab to study important introductory principles of genetics by developing hypotheses and designing and conducting matings between fruit flies with different mutations that you have selected.
Once you have examined the results of a simulated cross, you can perform a statistical test of your data by chi-square analysis and apply these statistics to accept or reject your hypothesis for the predicted phenotypic ratio of offspring for each cross. With FlyLab, it is possible to study multiple generations of offspring, and perform testcrosses and backcrosses. FlyLab is a very versatile program; it can be used to learn elementary genetic principles such as dominance, recessiveness, and Mendelian ratios, or more complex concepts such as sex-linkage, epistasis, recombination, and genetic mapping.
The purpose of this laboratory is to:
Simulate basic principles of genetic inheritance based on Mendelian genetics by designing and performing crosses between fruit flies. Help you understand the relationship between an organism’s genotype and its phenotype. Demonstrate the importance of statistical analysis to accept or reject a hypothesis. Use genetic crosses and recombination data to identify the location of genes on a chromosome by genetic mapping. Before You Begin: Prerequisites
Before beginning FlyLab you should be familiar with the following concepts: Chromosome structure and the stages of gamete formation by meiosis. Basic terminology and principles of Mendelian genetics, including complete and incomplete dominance, epistasis, lethal mutations, recombination, autosomal recessive inheritance, autosomal dominant inheritance, and sex-linked inheritance. Predicting the results of monohybrid and dihybrid crosses by constructing a Punnett square. How genetic mutations produce changes in phenotype, and beneficial and detrimental results of mutations in a population. Assignments
To begin an experiment, you must first design the phenotypes for the flies that will be mated. In addition to wild-type flies, 29 different mutations of the common fruit fly, Drosophila melanogaster, are included in FlyLab. The 29 mutations are actual known mutations in Drosophila. These mutations create phenotypic changes in bristle shape, body color, antennae shape, eye color, eye shape, wing size, wing shape, wing vein structure, and wing angle. For the purposes of the simulation, genetic inheritance in FlyLab follows Mendelian principles of complete dominance.
Examples of incomplete dominance are not demonstrated with this simulation. A table of the mutant phenotypes available in FlyLab can be viewed by clicking on the Genetic Abbreviations tab which appears at the top of the FlyLab homepage. When you select a particular phenotype, you are not provided with any information about the dominance or recessiveness of each mutation. FlyLab will select a fly that is homozygous for the particular mutation that you choose, unless a mutation is lethal in the homozygous condition in which case the fly chosen will be heterozygous. Two of your challenges will be to determine the zygosity of each fly in your cross and to determine the effects of each allele by analyzing the offspring from your crosses.