Inheritance of Traits in Fruit Flies
Genetics shows us that we inherit traits in many different ways. A perfect example to show us the different ways we inherit traits is fruit flies. Fruit flies are commonly used by scientists to conduct genetic experiments due to their reaction to the experiment being very quick. Scientists mainly look at how the flies inherit basic traits such as brown body color, or red eyes(basic trait flies are known as wild-type flies) from their parents, but sometimes they can come across some abnormal traits. Some of these abnormal traits include having a yellow body color or having curly shaped wings and have made scientists wonder how the flies have inherited these specific traits. So how do the flies inherit
…show more content…
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.
Table 2: Yellow Male x Wild-Type Female
Generation
Male Wild
Male Yellow
Female Wild
Female Yellow
P1
0
1
1
0
F1
52
0
57
0
F2
88
43
114
0
This next table follows a similar skeleton as the one before. The table gives us an outcome for when we cross the two parents with each other, and then gives us another outcome by crossing another male and female from the F1 generation(the first offspring) which creates the F2 generation. So if we look at the numbers for the F1 generation, we can get about a 2:2 ratio of 2 wild males to 2 wild females. Then, if we look at the F2 generation we get around a 1:1:2 ratio of 1 wild male to 1 yellow male to 2 female wild. So all of this data tells us that throughout all the generation, none of the offspring turned out to be female yellow.
Wild-type Male x Yellow Female
Cross: XY x XyXy
X
Y
Outcome:
Xy
XyX
XyY
- 2 wild female
Xy
XyX
XyY
- 2 yellow male
This Punnett square represents the offspring of a wild-type male and yellow female. The offspring outcomes of this square create a 2:2 ratio of 2 wild-type females to 2 yellow males. These outcomes correspond with
If your offspring genotypes include 2 GG and 2 Gg, the ratio would be: 2 GG : 2 gg (or 1:1 in the reduced form)
Now mate a mutant F1 female fly with a mutant F1 male fly. Out of the 50 F2 progeny, what percentage of flies are wild type and what percentage are mutant
You are also provided with a heterozygous female, and a homozygous recessive male for a genetic cross. In this particular female, all the dominant alleles are on one chromosome, and the recessive counterparts are on the other homologous chromosome. Due to a chromosomal condition, in the female no recombination occurs between the M and N loci. Normal recombination occurs between the L and M loci. Diagram this cross, and show the genotypes and frequencies of all offspring expected from this cross.
The figure below shows the result of multilocus analysis of offspring’s from a large family. Answer the following questions.
3. After a week, the flies that resulted from P – generation, F1, were FlyNapped and taken out by placing them on index cards. Paintbrushes were used to transfer them onto the index cards. They were sorted into the following categories – male Sepia, female Sepia, male Wildtype, female Wild Type – and counted, this was F1. Six Sepias (3 males, 3 females) and six Wildtypes (3 males, 3 females) were then added to two separate vials. The vials were placed on their sides to avoid any flies drowning. The flies remaining were disposed of properly (fly
Drosophila melanogaster is an important model organism in biological research and has been prevalent for over one hundred years. Fruit flies are used by researchers because they having many qualities that make them favorable in research including their genetics, size, and reproductive capacity. The goal of the experiment is to test the different genetic mutations and sex linked crosses that each generation of the fruit fly can make. This lab sets up crosses of flies that reproduce in two-week span. The parents for the initial cross in the F1 generation are homozygous recessive white- eyed females and wild type red-eyed males (Shoup). After two weeks, the F1 generation phenotypic ratios change for the F2 offspring. We expect that the
Drosophila melanogaster is a fruit fly. On average, they are about 3mm in length and prefer to live near spoiled fruit. They can be found on every continent of the world except for Antarctica. The Drosophila melanogaster egg us about .5mm long. It takes about one day after fertilization to develop and hatch into a worm-like larva. The larva eats and grown continuously, molting one day, two days, and four days after hatching. After two days as a third instar larva, it molts one more time to form an immobile pup. Over the next four days, the body is completely remodeled to give the adult winged form, which then hatches for the pupal case and is fertile within about only 12 hours. (ceolas.org)
The next class period, was the first sign of larva. The parent flies were anesthetized using flynap, and taken out of the test tube. The F1, generations mated and created F2 progeny of files. We repeated the process several times by anesthetizing the flies and recording their phenotypes by looking under a microscope. Once all the data was recorded for the
If we take S to represent the straight winged insects and a dominant gene and c to represent the curved winged insects. Then you use a punnet square or a test cross. As long as you have the genotypes of the parents then you are good to go. If the alleles of the fly are Sc, then they are heterozygous if its SS then they are homozygous.
The Drosophila melanogaster organism has been favored throughout decades as a model organism for its ability to be cultured in mass, has a short generation time, and, with a myriad of mutations to be mapped to the organism, organisms with certain mutations can be ready at hand to further study. The inception of the D. melanogaster research started in Columbia University at the hand of Thomas Hunt Morgan. Morgan’s different views in genetics led to questioning Mendel’s past research and finding faults in his inheritance patterns and ratios. Mutations in fruit flies were discovered in a small fraction of flies in 1907 by Frank Lutz who found some flies had extra venation and successfully bred them to all have extra venation over eight generations.
The fruit fly has an optimal life cycle which makes it convenient and efficient when studying its genetic information. A fruit fly incurs a life cycle that last approximately one and a half to two weeks. Its life cycle manifests in four phases respectively: egg, larva, pupal, and adult stage. Due to the short amount of time it takes a fruit fly to be reproduced and developed, a plethora of information can be learned in a very short period of time (Lewis 1998). Other benefits of using fruit flies are due to: low cost, production in large numbers, and easy production (Lewis 1998). In laboratory, a dihybrid cross was performed in order to determine the traits exhibited by the F2 generation.
In the F2 the gender of the flies were irrelevant to figure out the genotype. This is all because of the father fly. The father in this cross was a homozygous recessive individual for both the genes on the X chromosome and so all his female offspring will either be heterozygous or homozygous recessive at each gene. The males on the other hand only receive their X chromosome from the mother (father provides their Y chromosome) so all the alleles for these
The fruit fly Drosophila melanogaster is an extensively studied model organism. Its steadfast presence since the early 20th century, has led to significant findings and contributions in classical genetics, various areas of biological sciences, and biomedical research. This includes the discovery of the fundamental concept that chromosomes carry heritable traits (Pandey and Nichols, 2011). Its fully sequenced and annotated fly genome, homology similarity to the human genome, rapid life cycle, large number of progeny, easiness of culturing, and low maintenance expenses are the primary attributes that make it an excellent model organism convenient for study (Arias, 2008; Pandey and Nichols, 2011). Even more so, humans and D. melanogaster share
A gene is a trait that is passed down from one generation to another and gives an organism its characteristics. In this experiment, there are two different genes that affect whether a fruit fly, or Drosophila melanogaster, is winged or wingless. Most fruit flies have wings, this is the dominant trait. If an organism carries a dominant trait, that trait will always appear in the organism’s offspring. Compared to the number of winged flies, few fruit flies are wingless. Wingless is the recessive trait. If an organism carries a recessive trait and a dominant trait, the recessive trait will not show up in the organism’s physical appearance; however it will still be present in their genes (Mendelian Genetics, Biology). In this experiment, wingless
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.