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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plant. After that he came up with three lows of the concept of modern genetics which are Mendel’s low of segregation, Mendel’s low of independent assortment, and Mendel’s low of dominance. Mendel’s low of segregation, Mendel stats that every traits have two alleles and every gametes receive just one of these allele. The Law of Independent assortment states that the alleles for a separate trait is independently for another trait. Drosophila melanogaster, the famous fruit flies, the genetics’ scientists have used as model for many years in their experiments.
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
pigmentation.
Variation in selection pressures on the goldenrod gall fly and the competitive interactions of its natural enemies
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
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).
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
The idea of the project was to experiment breeding Drosophila Melanogaster (fruit fly) to figure out if certain genes of that species were sex linked or not (autosomal). A mono-hybrid cross and di-hybrid cross was performed. For the mono-hybrid cross, white eyed female and red eyed male were placed in one vial for them to reproduce. For the di-hybrid cross, red eyed and normal winged flies and sepia eyed and vestigial winged flies were placed in their vial to reproduce. In the mono-hybrid cross the results expected were within a 1:1:1:1 ratio. Expected results similar to the expected desired null hypothesis proposed with what the F1 parental generation breeds. The potential results would have had to have been within the ratios of 9:3:3:1. The results were clear and allowed the null hypothesis to be correct. The white eyed gene in the fruit flies is sex linked. Sepia eyes and vestigial wings are not sex linked and are examples of independent assortment.
Studying fruit fly mating behavior is very important because their generation length is so short and reproduction happens rapidly. 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
In this experiment, Mendelain Models are observed. The purpose of the experiment is to understand how traits are passed from one generation to the other as well as understanding the difference between sex linked and autosomal genes. One particular trait that is observed in this experiment is when a fly is lacking wings, also known as an apterous mutation. In this experiment, we will determine whether this mutation is carried on an autosomal chromosome or on a sex chromosome. The data for this experiment will be determined statistically with the aid of a chi-square. If the trait is autosomal, then it will be able to be passed to the next generation on an autosomal chromosome, meaning that there should be an equal amount of male and
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:
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. An individual can me homozygous dominant (two dominant alleles, AA), homozygous recessive, (two recessive alleles, aa), or heterozygous (one dominant and one recessive allele, Aa). There were tow particular crosses that took place in this experiment. The first cross-performed was Ebony Bodies versus Vestigle Wings, where Long wings are dominant over short wings and normal bodies are dominant over black bodies. The other cross that was performed was White versus Wild where red eyes in fruit flies are dominant over white eyes.
In the 19th century Gregor Mendel accomplished pioneered the first laws of genetics after crossing peas. He conducted an experiment with pea plants. He would use a paintbrush to transfer the genetic coding from one pea plant to another, so he could know exactly who the parents were. With the end of this experiment Mendel came up with two laws; Mendel 's law of segregation, and Mendel 's law of independent assortment. Mendel crossed over purple pea flowers with white pea flowers, which gave him purple pea flowers for the first generation also called F1. Since the offspring were all purple flowers Mendel understood that the purple gene was the dominant gene. Mendel decided to cross the F1 generation with themselves. Which resulted in three purple pea flowers and one white pea flower. By using basic Punnett square, and identify the genotype as PP and the phenotype as pp. This gave Mendel the following ratio of 3:1, three purple pea flowers and one
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.
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,