Drosophila melanogaster is a small, common fly found near unripe and rotted fruit. It has been in use for over a century to study genetics and behavior. He was the first to discover sex-linkage and genetic recombination, which placed the small fly in the forefront of genetic research.
Fruit flies are easily obtained from the wild and many biological science companies carry a variety of different mutations. In addition these companies sell any equipment needed to culture the flies. Costs are relatively low and most equipment can be used year after year. There are a variety of laboratory exercises one could purchase, although the necessity to do so is questionable.
They are small and easily handled. Virgins fruit flies are physically distinctive from mature adults, making it easy to obtain virgin males and females for genetic crosses. Flies have a short generation time days and do well at room temperature. Construct traps to catch wild populations of D. Gain an understanding of the life cycle of D. Realize many science experiments cannot be conducted and concluded within one or two lab sessions.
Hereditary information is located in genes. Combinations of traits can describe the characteristics of an organism.
Communicate and defend a scientific argument. Therefore, those teachers or students wishing to see where their mutations occur have a ready reference available. Since Drosophila has been so widely used in genetics, there are many different types of mutations available for purchase.
In addition, the attentive student may find mutations within their own wild-caught cultures since, due to a short generation time, mutations are relatively common compared to other animal species. This is the same as the well-known metamorphosis of butterflies. The larval stage has three instars, or molts. After the eggs hatch, small larvae should be visible in the growing medium.
If your media is white, look for the small black area the mouth hooks at the head of the larvae.
Some dried premixed media is blue to help identify larvae however this is not a necessity and with a little patience and practice, larvae are easily seen. In addition, as the larvae feed they disrupt the smooth surface of the media and so by looking only at the surface one can tell if larvae are present.
However, it is always a good idea to double check using a stereo microscope. After the third instar, larvae will begin to migrate up the culture vial in order to pupate. Introduction In order to incorporate fruit flies in the classroom, it will be necessary to maintain cultures of flies for manipulation in crosses and as a backup for any mishaps which may occur.
Culturing is very easy and it is recommended to have students maintain their own cultures of flies.Give us a call: Drains should be the initial inspection site when encountering an infestation. The adults are often seen flying in areas located away from the source of infestation. In the yearfruit flies had already been recognized as indispensable to genetic study and research and they remain so today.
Fruit fly populations are inexhaustible, simple to breed and are not costly subjects. Their genetic makeup is also incredibly simple.
Mendel’s Law Lab: Genetics & Fruit flies
Their chromosomes are large and undivided, allowing for easy observation. When the chromosomes of a fruit fly are stained with chemicals, they reveal straight, dark bands along their length.
These bands match the locations of particular genes. The chromosomes of fruit flies gave scientists their first glimpse of genetic variations between species and individuals. The Drosophila melanogaster is the most well known of fruit flies.
It has four chromosomal pairs: one that determines sex and three autosomal chromosomes. Each chromosome has two arms, referred to as the left and the right. The chromosomal localities of individual genes are identified either by recombination units or numerical locations on each of these arms. This allows for prediction and comprehension of recombination frequencies between two genes located in the same chromosomal arm.
Because female fruit flies often mate with more than one male during mating sessions, virgin fruit flies are necessary for scientific study.
Using fruit flies that have previously mated may result in mixed offspring, which skews experiment results. As a result, students can mate red- and sepia-eyed fruit flies in order to learn firsthand about dominant and recessive genes.
Fruit flies are also helpful in studying mutation. Studying the genetic makeup, transcription and replication of the fruit fly can assist in better understanding these processes in other eukaryotic organisms, such as humans. Fruit flies have been used as research subjects sincewhen Thomas Hunt Morgan studied them at Columbia University to better understand matters of heredity.
Fruit flies also make excellent research subjects because of their rapid life cycle. This allows scientists to study the effects of stimuli over the course of hundreds of generations within a matter of months.
Fruit flies have a very simple genetic structure, which makes them ideal for genetic research. It is useful to study mutant fruit flies, as their quick reproduction rate allows scientists to observe the advantages and disadvantages of certain mutations.
These fruit flies are also helpful in determining whether certain stimulants cause mutation. Some common mutations seen in fruit flies include wing structure and eye color variations. Mutant wings may be short or backward. Fruit flies are known for their red eyes, although mutations cause certain specimens to have golden or white eyes.
Mutations also sometimes result in eyeless flies. Mutants may exhibit yellow and black bodies, while the standard fruit fly is light tan in color. Share: Facebook Twitter Email. Find Your Local Branch Enter a zip code below to view local branches. Having trouble with Pests? First Name. Last Name.
Fruit Fly Facts Drains should be the initial inspection site when encountering an infestation. Fruit Fly Pictures Learn to identify this pest with these helpful pictures.
Fruit Fly Genetics In the yearfruit flies had already been recognized as indispensable to genetic study and research and they remain so today. Fruit Fly Chromosomes Their chromosomes are large and undivided, allowing for easy observation.BioLab Fly Genetics come to life as students study the fascinating physical traits of fruit flies and how characteristics are passed from parent organisms to their offspring.
Student Scientists Get Hands-On Practice With: F 1 Cross Breed two pure bred organisms to see how dominant and recessive genes affect the characteristics of the offspring. F 2 Cross See how specimens with mixed genotypes vary the results. Sex-Linked Cross Determine which traits are carried only through a particular chromosome and thus are linked with a gender.
Dihybrid Cross Do a cross between individuals that involve two pairs of contrasting traits. Fly Breeder Exercise the mind with this open-ended activity while analyzing twenty-six different physical characteristics. Learn By Doing. Students develop reasoning skills as they observe parental genotypes, build a Punnett square, predict the characteristics of the offspring and test their prediction.
This step-by-step investigation exposes students to simple and complex genetic principles. I nteractive Log BioLab Fly features a log that records progress and allows the teacher to track student learning. To order call Carolina Biological Supply Company at or order online www.
Teacher-Developed BioLab Fly follows tried and true educational practices as each student receives pre-lab instruction, thorough open-ended lab simulation, and post-lab reinforcement. A collection of printable worksheets is included on the CD.
Students use the Fly Editor to generate flies with 26 different characteristics. In-depth Lab Experience.
In four detailed labs, students study the principles of genetics and learn about dominant, recessive, sex-linked and autosomal characteristics.Developed at the University of Wisconsin-Madison, CGS allows students to perform virtual test crosses with model organisms.
Instructors can set the parameters for the populations under study, such as the number and type of traits in a population, the modes of inheritance and trait linkage.
Students determine which crosses to perform and interpret the resulting data. CGS can be used as a primary laboratory module for introductory biology or genetics courses, or as a supplement to a hands-on genetics module with real organisms. In addition to mice and Arabidopsis plantstest crosses can be performed with Drosophila melanogaster fruit flies using the CGS software. If you do not have an account and would like to explore some example populations for yourself:.
If you want to explore all of the features of CGS, you can: 1. Below is a screen capture of a Drosophila population being investigated:. Drosophila flies carry three sets of autosomes and two sex chromosomes. Their relatively fast life cycle and their ease of use made this common fruit fly an important historical model species, and they are still studied by geneticists today. Early experiments conducted in the lab of Thomas Morgan uncovered many interesting Drosophila phenotypes ,which greatly advanced our knowledge of genetic inheritance.
Students working with CGS are able to perform some of the same experiments that have lead to major breakthroughs in the field of genetics.
For more information about CGS, use the menu on the left to explore the website. Classical Genetics Simulator. Drosophila genetics simulation Developed at the University of Wisconsin-Madison, CGS allows students to perform virtual test crosses with model organisms. If you do not have an account and would like to explore some example populations for yourself: How do I get started? Click here to launch CGS in a new window. Choose a population to examine, and decide which test crosses you want to perform.
Below is a screen capture of a Drosophila population being investigated: Drosophila flies carry three sets of autosomes and two sex chromosomes. How do I get started?Labs demonstrating Mendelian genetics are illuminating for students but pose potential complications. Typical hands-on, in-person experimental models involve plants which grow slowly or fruit flies which require strict time-frames for particular steps — something nearly impossible for high school or a commuter undergraduate campus.
The advent of virtual labs allows students to struggle through mating strategies in order to draw conclusions about modes of inheritance by simulating actual matings without having to organize their real-life schedules around isolating Drosophila virgins.
Students must do subsequent additional crosses and analyze offspring to deduce the mode of inheritance. However both practice and non-practice versions are available to anyone who downloads the software, making it difficult to use this as an assessment tool for distance learners or as homework. It would, however, be easy to delete practice versions on classroom computers to make this an excellent in-class activity.
Progeny from one or more matings can be viewed in a summary chart that can be easily manipulated to show or hide sex, phenotype, etc. While a good tool overall, there are some drawbacks to the program. Additionally, some of the walk-throughs were written for a previous version of the program and have not yet been updated to reflect attributes of the new system. Finally, assessment is extremely limited since there are no quizzes or opportunities to record substantive conclusions at any point — such exercises would have to be developed separately by the instructor.
VCISE allows a user to review applicability to K—12 science standards by state, showing that the learning objectives of the program will integrate easily into a course curriculum. One must put flies in mating jars, place and retrieve the jars from incubators, anesthetize the flies, sort them under a microscope, etc. Whereas both programs allow one to keep track of mating results, VCISE allows the participant to save information about each step in a virtual lab notebook, again simulating a genuine lab operation.
Finally, this program helps students build a lab report: students follow prompts to build a report online with quantitative analysis along with qualitative answers and images from their notebook.
One of the best features of this software is that with minimal preparation, an instructor can set up a class code whereby students can save their work and build a report which can be monitored and graded online.
In summary, while both programs allow a student-directed approach whereby students choose fly matings and interpret the mode of inheritance based on offspring, the VCISE program is more ideally structured to visually engage students and facilitate instructor assessment of student learning. National Center for Biotechnology InformationU. J Microbiol Biol Educ. Published online May 6.
Robin Herlands Cresiski.Fruit Fly Simulation Lab- doing chi-square analysis
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These laws were discovered and formed using only pea plants. He used peas because peas are normally self-pollinating, but in this case Mendel could control whether they self-pollinated or not.
In his initial experiments, Mendel removed the stamens from some of the young flowers so that self-fertilization could not occur, then tied a bag around each flower so that cross-fertilization could not occur. After the pistils became mature, he artificially cross-pollinated them by dusting the stigma of pea plants with pollen of other pea plants that had factors for some contrasting trait.
In this experiment, Drosophila melanogasterfruit flies, will be used instead of pea plants. It is typically used because it is an animal species that is easy to care for, has four pairs of chromosomes, breed quickly, and lays many eggs.
If we believe that the law of dominance and segregation is accurate, then if we mate a red eyed female with a white eyed male, the characteristics would properly cross over to the offspring.
It was observed a small but discrete variation known as white-eye in a single male fly in one of the bottles. I bred the fly with normal red-eyed females. All of the offspring F1 were red-eyed. Brother—sister matings among the F1 generation produced a second generation F2 with some white-eyed flies, all of which were males. To explain this curious phenomenon, I developed the hypothesis of sex-limited—today called sex-linked—characters, which I assumed were part of the now called X-chromosome of females.
Other genetic variations arose in my stock, many of which were also found to be sex-linked. Because all the sex-linked characters were usually inherited together, I gradually became convinced that the X-chromosome carried a number of discrete hereditary units, or factors. I adopted the term gene, which was introduced by the Danish botanist Wilhelm Johannsen inand concluded that genes were possibly arranged in a linear fashion on chromosomes.
Much to my credit, I rejected my skepticism about both the Mendelian and chromosome theories when I saw from two independent lines of evidence—breeding experiments and cytology—that one could be treated in terms of the other. White Gene, abbreviated w, was the first sex-linked mutation ever discovered in the fruit fly Drosophila melanogaster.
I collected a single male white-eyed mutant from a population of Drosophila melanogaster fruit flies, which usually have dark brick red eyes. Upon crossing this male with wild-type female flies, I found that the offspring did not conform to the expectations of Mendelian inheritance. The first generation the F1 produced 1, red-eyed offspring and three white-eyed flies, all males. The second generation the F2 produced 2, red-eyed females, 1, red-eyed males, and white-eyed males.
I named this trait white gene, now abbreviated w.
This is where the now called Y chromosome was introduced. The Y chromosome is one of two sex chromosomes in mammals, including humans, and many other animals. The other is the X chromosome. Y is the sex-determining chromosome in many species, since it is the presence or absence of Y that determines male or female sex.
In mammals, the Y chromosome contains the gene SRY, which triggers testis development. The DNA in the human Y chromosome is composed of about 59 million base pairs. The Y chromosome is passed only from father to son, so analysis of Y chromosome DNA may thus be used in genealogical research.Pearson, as an active contributor to the biology learning community, is pleased to provide free access to the Classic edition of The Biology Place to all educators and their students.
The purpose of the activities is to help you review material you have already studied in class or have read in your text. Some of the material will extend your knowledge beyond your classwork or textbook reading. At the end of each activity, you can assess your progress through a Self-Quiz.
To begin, click on an activity title. In this laboratory you will study the patterns by which physical characteristics are transmitted from generation to generation. By breeding fruit flies Drosophila melanogaster of unknown genetic composition and studying the traits and ratios seen in their offspring, you will determine whether a trait follows a monohybrid or dihybrid pattern of inheritance and whether it is sex-linked or autosomal.
You will use statistical analysis to support your conclusions. The lac Operon in E. LabBench Activity Genetics of Organisms by Theresa Knapp Holtzclaw Introduction In this laboratory you will study the patterns by which physical characteristics are transmitted from generation to generation. All Rights Reserved.