Abstract
In this experiment fruit flies have been used as models for showing the Mendelian inheritance. Fruit fly (Drosophila melanogaster) is a better organism to study genetics because it has many physical traits, short life cycle, and produce many offspring. In this experiment, two crosses were done, each of the obtained two generation F1 and F1. The first cross was between wild-type males (red eyes, normal wings) and mutant Females (white eyes, apterous wings).The second cross was between mutant males (white eyes, apterous wings) and wild type females (red eyes, normal wings) .The inheritance of traits which observed in the crosses, were tested. We have test our hypothesis by using Chi-square analysis for F2’ generation of crosses. Our result about inheritance of traits in the crosses is that mutant traits are X-linked recessive inheritance.
Introduction
Gregor Mendel who discovered the study of genetics. He started studying the genetic inheritance in pes
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Because of the size, produce many offspring, easy to discover the mutation, and having a short life cycle, fruit fly has been the good model to study genetics. The Drosophila life cycle starts after the male and the female mate. The female produces the fertilized eggs. In 24 hours each of the eggs hatch to the next stage which the 1st instar lava. After the next 24 hours, the 2nd instar lava shows up. Next day, the 2nd instar lava goes to 3rd instar lava. Two days later, the 3rd instar lava goes to the next stage which pupate. In about 5 days the pupate forms to a Drosophila. The fruit flies have a different body features between the females and the males which makes us have the right matching in our crosses. There are four features we can distinguish between males and females which are: Sex combs, External genitalia, number of abdominal segments, and abdominal
Variation in selection pressures on the goldenrod gall fly and the competitive interactions of its natural enemies
The purpose of our experiment was to test whether or not the Wisconsin Fast Plants, or Brassica rapa, followed the Mendelian genetics and its law of inheritance. First, after we crossed the heterozygous F1 generation, we created an F2 generation which we used to analyze. After analyzing our results, we conducted a chi-square test for for both the F1 and F2 generations to test their “goodness of fit”. For the F1 generation we calculated an x2 value of 6.97, which was greater than the value on the chi-square table at a p-value of 0.05 and 1 degree of freedom (6.97 > 3.84). This meant that we had to reject our hypothesis that stated there would be no difference between the observed and expected values. This showed us that the F1
In science, these fruit flies can be used to study genes and mutations relatively quickly because of the limited life span. Knowing mating behaviors can help scientists better understand their results and improve their experiment designs to reduce
The fruit fly, or the Drosophila melanogaster, was used in this experiment to study patterns of inheritance. It only takes a fruit fly 14 days to develop from an egg to an adult and then 12 hours before they become reproductive, so these factors made the fruit fly a good species to study, because we had enough time to do crosses. We were investigating the patterns of inheritance in the eye color and the wings. The wild type flies had red eyes and full wings, while the mutant phenotype had brown eyes and no wings. We also had to study the sexes of the flies. The male flies had darker abdominal tips and sex combs on both of their forearms. For the results, my group had predicted as follows:
We then allowed the larvae to hatch, and counted and recorded the total number of flies, the phenotype, and the sex. After taking down all this information this would allow us to perform a F1 cross, we made sure to examine the flies carefully since we needed virgin flies. We prepared a new vial with the a 1:1 ratio of medium and water. After recording the data of the F1 generation, and picking out the virgin flies for the crossing, and we killed of the rest of the flies using the oil method. After some time passed the F1 generation had larva in the vial. Once we noticed the larva we had to put the flies to sleep and collect the data. We then had to prepare another two new vials and medium and water. Carefully observing the flies and picking out three males and three female virgin flies to place into the new vial. Than killing of the other flies. After about a week we had the F2 generation. This was the most important generation, it was what we were looking for to allow us to observe and compare our experiment to Mendel’s experiment. We were looking for a 9:3:3:1 ratio with our flies. Using a basic Punnett square table and the crossing that we had accomplished our results should have looked like the following Punnett square.
Examining the Crosses Between Drosophila Fruit Flies Introduction The major topic of this experiment was to examine two different crosses between Drosophila fruit flies and to determine how many flies of each phenotype were produced. Phenotype refers to an individual’s appearance, where as genotype refers to an individual’s genes. The basic law of genetics that was examined in this lab was formulated by a man often times called the “father of genetics,” Gregor Mendel. He determined that individuals have two alternate forms of a gene, referred to as two alleles.
Mendel wrote that genes are passed from parents to their children and can produce the same physical characteristics as the parents.
Knows as the “Father of Genetics” Mendel is said to have started the conversation leading DNA’s discovery. In 1866, Mendel concluded that genes are formed in pairs and are passed down from parents as distinct units. His experiment consisted of a control plant and he tracked the segregation of those genes in the appearance of them in the offspring. He labeled them as dominant and recessive traits. Through his discovery, Mendel established the rules that future generations of scientists would use in their research. These rules known as “Mendel’s Laws of Heredity” and include three rules. These include The Law of Segregation (a gene pair defines each inherited trait.), The Law of Independent Assortment (Genes for different traits are sorted separately from one another), and The Law of Dominance (An organism with alternate forms of a gene will express the form that is dominant.). Innovative and time-consuming, Mendel’s work went extremely underappreciated and was not put to use until after
Biologist, Gregor Johann Mendel, discovered how traits passed from one generation to the next. Mendel studied and used pea plants to discover the principles that rule heredity. He found that each parent, father, and mother pass down traits to their offspring, who inherit different combinations of their recessive or dominant alleles-terms introduced by Mendel during the 19th century. Mendel introduced important principles teaching us that recessive traits will only be shown in the phenotype if both alleles are recessive. Mendel’s laws of inheritance include the Law of segregation and the Law of independent assortment.
17. Fruit flies normally have eight chromosomes. The diagram below shows the result of meiosis in three fruit flies to produce gametes with the number of chromosomes indicated. The male then mates with both female A and female B to produce three zygotes (1, 2, and 3).
In order to figure out the genes responsible, there are several other factors that must be determined. These factors include the number of genes involved, if each gene is x-linked or autosomal, if the mutant or wild-type allele for each is dominant, and if genes are linked or on different chromosomes. Proposed crosses include reciprocal crosses between the pure-breeding mutants of strains A and B with the wild-type will help determine if the genes or sex-linked or autosomal, in addition to which alleles are dominant (8). Another proposed cross includes complementation crosses between pure-breading mutants from strains A and B to determine if one or two genes are involved (8). Furthermore, testcrosses between F1 progeny and pure-breeding recessive mutants from strains A and B, which will help determine if genes are linked on the chromosome or if they assort independently (8). These proposed crosses are shown in the attached
The F2 punnett square shows that there should not be a female fly that has apterous wing mutation. Our observed experiment showed that female flies are capable of forming in the F2 Generation. Therefore, the mutation is located on autosomal chromosomes. In trial 1, the p value is not significant. This could be due to the fact that the male to female ratio in the F1 generation was unequal. In trial 2, the p value is significant and likely due to chance. The probability error is between 1 % and 5%.
Conclusion for class di-hybrid cross: The p value 0.779 is in the non-significant range in the chi square table. The null hypothesis is therefore correct. Sepia eyes and vestigial wings in the flies is a mutation in the genes that is not linked meaning it is a product of independent assortment.
Darwin, Charles. From The Origin of Species. New York: P.F. Collier and Son Corporation, 1937. 71-86; 497-506.
Gregor Mendel, born as Johann Mendel, is considered to be one of the most significant historic scientist of all time. He was an Austrian scientist and monk and is best known as the “Father of Modern Genetics.” He founded the science of genetics and discovered many things that dealt with heredity that still applies to our world today. He is remembered for paving the way for scientists and future generations to come. Unfortunately, Mendel’s work went unnoticed until 16 years after his death and 34 years after he published his research. Though Mendel lay covered in his grave, his work would eventually be uncovered. Although Mendel was not there to see it,