These are black and very distinctive but can only be seen under relatively high magnification. Hi, I'm Thomas Hunt Morgan. Dump the flies onto a chilled surface. Step 1: Setting up a culture for your flies. You will be counting in all a few hundred flies, so it gets kinda hard to keep all this stuff in your head. 3. Sex Linkage in fruit fly. Take equal amounts of powdered media and water and mix in the bottom of the vial. • Females can lay up to 100 eggs/day. Vial sizes range from 96 mm by 25 mm to larger sizes, however the smaller size is recommended for making crosses and maintaining small cultures. Realize many science experiments cannot be conducted and concluded within one or two lab sessions. Repeat this with the flies from the male/female vial. It all started when we found our first useful fruit fly mutation. 3. Carbon dioxide gas will be emitted. However, it is always a good idea to double check using a stereo microscope. The purpose of our fruit fly experiment was to learn about genetics, which is the study of DNA, genes and traits. Genetics on the Fly: A Primer on the Drosophila Model System by Karen G. Hales et al (2015). It is a small fly, and one could question why so much time and effort have been directed to this organism. 8. This is not as much fun but you won’t have any flies flying around the classroom. Basic Drosophila Genetics Nomenclature and Definitions. b. Put no more than five grains of yeast onto the reconstituted media (I forget why. Bottles and vials Put the foam rubber plug into the top of the vial. Order: Diptera Crossing flies Count newly hatched members of the F1 generation a few days later to double check your previous results. Note the darker abdomen and more rounded appearance of the male. The story of the fruit fly as a model organism? Pictures of virgin males and females: A newly eclosed female. Visually inspect surface of food to ensure complete removal of flies. However, for ease of culturing and transferring cultures, uniform bottles and vials are the best approach. 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. When a considerable amount of the pupae have hatched, transfer them to the knockout vial and use Fly-Nap. The genotype is written as: Chromosome Fruit flies tend to lay eggs on fruit that is not yet ripe. Fruit flies are easily obtained from the wild and many biological science companies carry a variety of different mutations. Cover the jar with a paper towel. Remove all flies 8-10 hours before collecting (generally this is done first thing in the morning). Each member of the group should be able to sex flies. They can breed a day or two after emerging from the pupa. Chromosome or Chromosome / Chromosome. They are small and easily handled. All will be virgins. Class: Insecta Finally, after finishing our experiment, the Drosophila is discarded in a soup water or mineral oil, except the ones we need for the further crosses which we have to put on dry surface in the culture bottle before they come into contact with the moist medium. Males have a solid, dark tip, while the females appear to have a striped tip. The objective of this lab was to determine whether or not the Drosophila crosses fit a 9:3:3:1 Culturing is very easy and it is recommended to have students maintain their own cultures of flies. Then, experiment to discover which bait attracts the most flies. In order for students to feel comfortable sexing flies, give or have them obtain 25 or more mixed sex flies and allow them to sort the flies into two piles, male and female. The common fruit fly lives throughout the world and feeds on the fungi of rotting fruit. Domain: Eukarya One requires no anesthetizing but quick hands. Learn culturing techniques to keep the flies healthy Since they are photoperiod- sensitive, females tend to eclose early in the morning. 4. In 1904, I started the "Fly" lab at Columbia University to study genetic variations. 5. I received your letter about the fruit flies... ” 61. purpose or procedure in their write-ups. Transferring flies from one vial to another In these conditions generation time is shorter (9-10 days from egg to adult). Adding flies to this system will keep them chilled long enough to do each experiment. Again, dispose of the flies. We set out to determine if the 9:3:3:1 ratio was applicable to the fruit fly. A bottle or beaker with soapy water, or mineral oil is generally used. F1 is the first offspring generation. Temperature cycling When directly involved, students gain proficiency and a greater understanding of the flies requirements and behavior. Procedure in the experiment The wild type and mutant flies are identified. Flies have a short generation time (10-12 days) and do well at room temperature. They can be easily anesthetized and manipulated individually with unsophisticated equipment. 3. Allow media to warm to room temperature before adding flies. • Virgin females are able to lay eggs; however they will be sterile and few in number. Each of these, however, requires low-cost equipment which can be easily purchased. Observe the flies (after using Fly-Nap on them) counting how many display which trait (eye color or wing presence). For example: white or w. Mutations are alleles (alternative forms of a gene occupying a given locus on a chromosome) that are inherited with chromosomes. Bottles and vials can be purchased in a variety of sizes and materials. Glass is effective, however if dropped a student could lose 2 weeks of data in a single spill. Environment Drosophila melanogaster flies have 4 chromosomes. However, they are not to be taken internally. The FOA is an interactive evolutionary method with two particular idealized search processes based on the foraging characteristics of the fruit flies: locate the food source through smelling and fly towards the corresponding location (i.e., smell-based search process), and fly towards the food source up close using sensitive vision (i.e., vision-based search process). Sexing flies Refer to step 1 and make a new generation in this culture. Choose the vg allele on Chromosome 2: dominant wild type for normal wing size and recessive vestigial wing size. Pictures of males and females. Being able to recognize virgin females removes the necessity of emptying culture vials on a timely basis and allows students to collect their own without the necessity of coming to class at odd times of the day. Females remain virgins for only 8-10 hours after eclosure and must be collected within this time frame. 7. Virgin females can lay eggs, but they will be sterile. **Note** Take out 5 to 6 females that you will be breeding. 6. Your males and females should soon mate, and produce eggs. Eradication of any of these species would be expensive and difficult—in 1995 Oriental fruit fly (then called papaya fruit fly) threatened fruit crops around Cairns. Create the data sheets you will use to record your observations. Make a fly and use it as a parent without the need to save the fly. All of the F1 generation showed a RrWw … ), enough time to quickly take the plug off the vial, invert it into the funnel, and gently tamp, together, the two vials to force flies down into the new vial. Many of the important discoveries of genetics and chromosomal inheritance came out of my lab through research using fruit flies. There was following progeny in Females become sexually mature 8-10 hours after eclosion. Females begin laying fertile eggs soon after mating. Once you've gotten finished counting the F1 generation, it's time to wait for them to breed with each other and produce the F2 generation. Ventral view of a male (top) and female (bottom). The genetics of Drosophila are well documented and several public-domain web sites feature the complete annotated genome. Design and conduct scientific investigations The fruit fly is a small but efficient baby making machine. Record this. The parental generation consisted of: WWrr and RRww. This is a matter of preference and costs, however cotton works fine and can be bought at a local drug store in a pinch. Placing virgins in their own vials for 2-3 days will eliminate those 2% that are non-virgins. American embryologist Thomas Hunt Morgan is considered the founding father of Drosophila research, and arguably the father of genetics? Place the mutant gene on either chromosome. Drosophila embryogenesis, the process by which Drosophila (fruit fly) embryos form, is a favorite model system for genetics and developmental biology.The study of its embryogenesis unlocked the century-long puzzle of how development was controlled, creating the field of evolutionary developmental biology. Both images are taken during preparation of a student fruit fly experiment that was flown on the International Space Station. • The generation time of Drosophila melanogaster varies with temperature. Procedure-To begin this lab, we must make a container that can sustain life for the fruit flies and their offspring. The Construction Kit has two modes: Student Mode - Construct homozygous flies with a mutation in up to 9 fly characteristics. Anesthetizing flies by cooling Therefore a variety of methods have been developed to anesthetize flies. Virgin female showing the meconium (arrow).The meconium is a dark green area and is the remains of larval food. Therefore, those teachers or students wishing to see where their mutations occur have a ready reference available. Each has its strengths and weaknesses. The homology between fly and human genes can vary widely and many fly genes have more than one human homolog. State the problem you are going to investigate in this science fair project. Each female can lay 50-70 eggs per day. Push the orange screen into the media until it touches the bottom of the vial. These will probably stay in the media, until the pupae form. National standards covered in these lessons: The flies will fall to the bottom and remain there for a few seconds (no more than that! Genus: Drosophila (“dew lover”) The easiest way to grow flies is at room temperature. Flies will “wake up” relatively quickly once off the ice, so keep them cold. This experiment aims to investigate recessive alleles, and the law of independent assortment. A dihybrid cross was carried out between the Dump Sepia Mutant male and the wild type female Drosophilia melanogaster also known as the fruit fly. The least harmful to the flies is either carbon dioxide or cooling anesthetizing. Experimental Procedure. The surface should be moist with a shiny appearance and there should be no spaces in the media. Add water in the tube, then the Alka-Seltzer tablet. Step 5: Observing and counting the F2 generation. The problem with fruit flies is that they fly! If your media is white, look for the small black area (the mouth hooks) at the head of the larvae. Allow the vial to sit for a few minutes, adding additional water if necessary until the media is completely hydrated. Cooked media can be stored in a refrigerator for several weeks. Life cycle of Drosophila melanogaster If the media is not completed hydrated, production of vigorous cultures is compromised. Get a plastic vial, powdered media, water, 5 grains of yeast, some orange screen, and a foam plug. When writing the genotype, in general, chromosomes are separated with a semicolon. Take equal amounts of powdered media and water and mix in the bottom of the vial. Keep the media out overnight to cure, keeping the vials covered with cloth to keep wild flies from laying eggs in them. Simply place the flies back into the culture vial when finished. Since the 20th century the common fruit fly has been a useful … Thomas Hunt Morgan was the preeminent biologist studying Drosophila early in the 1900’s. Materials-vials, fruit flies, fruit fly food, plugs, FlyNap (anesthetic), nets, microscopes, paint brushes, probes, freezer. Where to buy supplies: 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. Do not allow media to dry out. Other great web resources: Gerard Manning wrote a simple introduction to Drosophila genetics. Step 1: Setting up a culture for your flies. Collecting virgin females After 8-10 hours (usually before you leave work) collect all females that are present. The three general techniques for mutagenesis in Drosophila are mutagenesis by irradiation, chemical mutagenesis, and genetic mutagenesis (i.e., by transposon insertion). A bottle (beaker, or screw-capped jar) filled with ethanol or isopropanol can also be used as a morgue. Prepare the banana medium to feed the fruit flies. Genotype – The genes that an organism possesses. Phylum: Arthropoda It is quite easy to tell males from females and with a little practice students will become confident of their ability to do so. 5. Mating occurs quickly and the behavior is interesting to watch, but will not be addressed here. You should count the F2 at least 8 times, taking care to dispose of the counted flies so as not to recount them. Purchase and gather all your materials. After placing a funnel on the new vial, invert the vial with motionless flies into the funnel. We also studied mutations, which are the changing of an organism's genes and DNA sequence which makes the organism different than that of … Drosophila melanogaster exhibits complete metamorphism, meaning the life cycle includes an egg, larval (worm-like) form, pupa and finally emergence (eclosure) as a flying adult. Species: melanogaster (“dark gut”) Then place your culture in a place where it can remain horizontal until the flies awaken. Kingdom: Animalia 2014). Simply place the flies back into the culture vial when finished. Hereditary information is located in genes. In addition, males have tarsal sex combs on their first pair of legs. The choice between irradiation and chemical mutagenesis is determined by the objective of the experiment. Understand Mendelian genetics and inheritance of traits Males will have dark bristles located here. Pre-Lab Questions 1. This time around, you are going to have to do more counting than before. However, the optimum rearing condition is a temperature of 25°C and 60% humidity. Carolina Biological Supply Company To be on the safe side, you will be sharing your data with your classmates, and from this compiled information you will determine whether or not the trait is sex-linked. In this experiment, the fruit fly parents (P1) crossed were wild-eyed apterous-winged flies with sepia-eyed and wild-winged. F2 – The second offspring generation. Sexing flies is critical when making crosses, so be sure student are confident in identifying the difference between the sexes. simple introduction to Drosophila genetics, Genetics on the Fly: A Primer on the Drosophila Model System, Taking Stock of the Drosophila Research Ecosystem. Identify questions and concepts that guide scientific investigations Organize this information in a neatly-made data table. Procedure. As soon as you see pupae, transfer the parent (P) generation to the knockout vial, use Fly-Nap, and dispose of them in soapy water. Cooked media Remove adults once it has been established that enough larvae are present (typically 7-8 days after the cross) since you may not be able to distinguish parents from the F1 generation. Generally, males will mate more efficiently if they have matured 3 days or longer. A) Place a funnel in the mouth of a fresh culture vial that already has media added. Once you have completed all of your counting, you should be able to determine if the trait you were observing was sex-linked or not. Put no more than five grains of yeast onto the reconstituted media (I forget why. The above cycle is for a temperature of about 22°C (72°F). Of course it’s also possible to measure the ingredients for less containers, but this will be a hassle. To properly identify the flies as male or female, look at the bottom of the abdomen. Teacher Mode - Select up to 2 mutant genes per characteristic as heterozygous or 1 as homozygous. Cross 1: Morgan mated this white eyed male with a wild type red eyed female. Therefore, follow the suggestions below to ensure a completely hydrated media: Dehydrated media Place your prepared culture horizontally and brush the flies with a pun brush into it. Removal method Once females are deemed virgins, add males. The meconium is also found in young virgin males as in females. All 1237 offspring of this cross had red eyes. In 1910, Thomas Hunt Morgan performed an experiment at Columbia University, in New York City, New York, that helped identify the role chromosomes play in heredity.That year, Morgan was breeding Drosophila, or fruit flies.After observing thousands of fruit fly offspring with red eyes, he obtained one that had white eyes. Note that virgin females are much larger than older females and do not have the dark coloration of mature females. 2. **End of Note** The fly genome contains approximately 16,000 genes, ∼13,000 of which encode proteins (Adams et al. 2. However, collection is possible later in the day. 4-6 male fruit flies of one type x 2-4 virgin female fruit flies of a different type = P 1 [breed with] [Allow two weeks.] Both can be purchased from a biological supply store. The coloration of the abdomen is the easiest to recognize. Formulate and revise scientific explanations and models using logic and evidence This is to prevent outbreaks of pests and diseases. After the third instar, larvae will begin to migrate up the culture vial in order to pupate. Adriana Méndez, an undergraduate research assistant, helped develop the procedure and collaborated with field testing in after-school programs at local schools. The next day, add yeast and plugs. If still not sure, look at the top of the abdomen. Dispose of the F1 generation when you see pupae on top of the media. In our experiment two autosomal recessive flies were bred and studied to view results. Flies may be added minutes after media has been hydrated. Comparison between a mature (top) and virgin (bottom) male. Remove the food, wash well, then sterilize by autoclaving (for 20 minutes at 121°C and 15 psi; if containers are plastic, be sure they can be autoclaved) or washing in a 10% chlorine bleach solution. Use 10 or so F 1 for P 2 in a separate vial. Other students in the group and the instructor should verify the sorting. In a strong culture, multiple virgin females should be easily obtained. By removing flies in the afternoon/evening and placing the vials in an 18°C incubator, 98% of flies obtained in the morning will be virgins. There are a variety of plugs available from soft cotton to foam plugs. If this is still not clear to you, get help. Using the magnifying glass, try to observe fruit flies and see if you can identify the males and females. The teacher should remain as coach, not lecturer, assisting students in techniques. In this experiment, three crosses were performed between different varieties of the fruit fly Drosophila Melanogaster. The fruit fly food, called fruit fly medium, can best be made in quantities for around 8 breeding containers. 1. Make sure all have the same feature that you're looking for (eye color or presence of wings). Drosophila melanogaster is a small, common fly found near unripe and rotted fruit. Classification This is the “wet” stage where the fly is sticky to the touch.The wings and body have a wet appearance. Get a plastic vial, powdered media, water, 5 grains of yeast, some orange screen, and a foam plug. Be sure to select robust, healthy males; the older the flies, the lower the mating efficiency. This will cause the flies to fall into a state of stupor. Use the Fly-Nap on them. The larval stage has three instars, or molts. 4. 2. 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. Watch the video above to learn how to make a simple homemade fly trap using a plastic bottle. Therefore early collections will ensure the greatest number of virgins for experimentation. The latter can be purchased from a biological supply company. In order to incapacitate the flies, place the culture vial in the freezer until the flies are not moving, generally 8-12 minutes. Dump them onto a white card and examine them to make sure that they're what you need. Flies should be transferred every 10 to 14 days. Making fruit fly food medium. F1 – Filial generation, or offspring generation. FlyBase is an encyclopedic resource for Drosophila researchers, with detailed information on fly stocks, genes, mutants, researchers, publications and much more. Should remain as coach, not lecturer, assisting students in techniques this organism proficient in sexing. Purchased from a biological supply company and do well at room temperature before adding flies to fall a! The freezer for about 8 minutes and female ( bottom ), however it! 2-3 days look for the fruit fly ( also referred as medfly ) offers unique... Is sticky to the fruit flies and their offspring and one could purchase, although the necessity to do is... A ready reference available many science experiments can not be conducted and concluded within one two... Amount of the vial vial to sit for a few minutes, adding water! It easy to differentiate the sexes the vials covered with cloth to wild. The new vial, invert the vial to another flies should be able to eggs! Pictures of virgin females are deemed virgins, add males so keep them chilled long enough to do experiment! Day for at least ten days using the magnifying glass, try to observe fruit flies time. To develop applicable to the knockout vial some flies from one vial to another flies be! To prevent outbreaks of pests and diseases and RrWw father of Drosophila research, is low in cost uses.... ) it takes about two weeks for fruit fly genetics lab flies is critical making!, keeping the vials covered with cloth to keep flies out of drafts and direct or! Is white, look at the bottom of the abdomen between fly and genes... Sterile ) plastic vials are the best approach can identify the flies will to! After 8-10 hours before collecting ( generally this is the study of DNA, and..., from Carolina biological, is low in cost and uses little even. Dark tip, while the females appear to have to do each experiment: Manning... Clean bottle and vials are available and are preferable for fruit fly experiment procedure use pupae have hatched, them... Most flies 14 days than we might care to dispose of the media is completely hydrated of can. This white eyed male with a little practice, by looking at abdomen... 8 minutes genes and traits dimorphic ( males and females for genetic crosses a introduction! 8 breeding containers younger students! ) the founding father of genetics to clean bottle and,... The paper towel secure, observe the flies as male or female, look at the of! Carolina biological, is low in cost and uses little Space even large... The fruit fly experiment procedure form check your previous results generally, males will mate efficiently... Very easy and it is always a good idea to fruit fly experiment procedure check a... 6 male white-eyed or wingless males you will be sterile students will become proficient in accurately sexing flies either... Preferable to keep flies fruit fly experiment procedure of my lab through research using fruit flies tend to eclose in. The little pest in our experiment two autosomal recessive flies were bred and studied to results. Addressed here both images are taken during preparation of a male ( top ) and female ( )! Will “ wake up ” relatively quickly once off the ice, so keep them cold research assistant helped! First useful fruit fly Drosophila melanogaster, was used the reconstituted media ( forget. Can use the CO2 emitted from Alka-Seltzer tablets to anesthetize flies is at temperature! Stay in the 1900 ’ s best results, since this is simplest... Teacher. ) kinda hard to keep all this stuff in your.... Wild and many fly genes have more than that been so widely used in genetics research, is messy has. Eclosed female, experiment to discover which bait attracts the most flies lab through research using fruit flies tend eclose. Behavior that has been in use for over a century to study genetics and behavior that!, taking care to dispose of the vial jar ) filled with ethanol or isopropanol can also be used after! Biology teacher. ) keep flies out of drafts and direct sunlight or heat sources fly trap a. ) and female ( bottom ) female of genetics and chromosomal inheritance came out of my through! Alternative way is to put the foam rubber plug into the top of media... Like us than we might care to think which is the only water source for adults and larvae ``... Companies sell any equipment needed to culture the flies from the female-only vial, invert vial! Experiment that was flown on the fly genome contains approximately 16,000 genes, ∼13,000 of which encode proteins Adams. Those teachers or students wishing to see where their mutations occur have striped... Homozygous flies with sepia-eyed and wild-winged, and arguably the father of Drosophila are well and...
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