Abstract
Drosophila melanogaster was used for this study for their fast reproduction cycles, fast regenerations, large amounts of offspring for each generation and their capability of living in a small limited space. The dominant or recessive genotype could be determining by the used of Mendelian genetic ratios for wild-type to mutant’s genes. The mutation that this study focuses on is the defects of the phenotypes in the common fruit fly, example; wing shape, wing sizes, body color and what the main focus of this experiment is dark eye pigment of the flies. These mutations were followed for three generations, collectable data for wild-type and mutants was obtained for each of the Drosophila melanogaster generations. The flies were
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Gender isn’t a key factor when it comes to determining a autosomal inheritance, Only sex-linked chromosomes like X or Y have an effect on the ratios for male and females having mutant alleles. This phenomenon is cause by the specific genome that each gender has, males have the XY chromosomes for sex and females have XX sex chromosomes. The reason for using Drosophila melanogaster flies is for their great genetics and fast reproduction that allows us to see in a short period of time the Mendelian genetic ratios from one generation to the other. Among this reason many others are in great importance as well, the common fruit fly has the same type of sex chromosomes as of humans, as mention previously in the text male flies have the same XY sex genes as male humans and same for female flies and female humans having XX sex genes. The fast regeneration, short life span and large number of offspring makes this specific organism a prime species to examine and study for better understanding of the Mendelian genetic ratios. Research was done on Drosophila melanogaster for the genetic analysis of sex chromosomes, meiotic mutations and their effect on recombination, disjunctions and their dominance (Baker and Carpenter, 1972). The mutation that is specific
The parents are both homozygous. The homozygous dominant would represent the wild type. And the homozygous recessive would represent the other fly parent of a different strain. The F1 generation would consist of 100% Wild Type but they would all be heterozygous in carrying the recessive gene.
To set up this experiment, two twenty-five gallon aquariums, 3 petri-dishes, 200 flies, rotten bananas, and yeast were used. The bananas chosen to be an accelerant for the growth of the yeast and were frozen so they would be easier to cut. The yeast was used because the drosophila melanogaster prefer this as a food source. The vestigial and wild type flies were sexed (to determine their sex), sorted, and counted. An initial population size of 100 total flies was decided so that it would be easier to determine the phenotypic percentage of the total population. Fly paper was placed in one of the sets of cages to impose a method of natural selection as well as the sexual selection which is being solely tested by the other set of cages.
Introduction: The intention of this lab was to gain a better understanding of Mendelian genetics and inheritance patterns of the drosophila fruit fly. This was tasked through inspecting phenotypes present in the dihybrid crosses performed on the flies. An experimental virtual fly lab assignment was also used to analyze the inheritance patterns. Specifically, the purpose of our drosophila crosses is to establish which phenotypes are dominant/recessive, if the traits are inherited through autosome or sex chromosomes and whether independent assortment or linkage is responsible for the expressed traits.
melanogaster, leaving B and D to be our mutants. Before crossing our populations, we made not of each one’s phenotype in order to see how crossing them would affect their phenotypes: Population B flies had no wings and red eyes, population D had full wings and black eyes and population G had full wings and red eyes. We expected the resulting phenotypes to be some sort of combination, revealing which traits were dominant. However, what we did not expect was the abnormal mutant that arose in a couple of our populations.
The conducted experiment assists in determining an unknown mutant allele found in Drosophila melanogatser. Mutant 489 illustrates a defect in eye pigmentation, which displays a dark brown eye color verses the brick red eyes in wild type flies. Based on the appearance our 489 mutation we've names our mutant rust.
It would be expected that the mutant F1 flies would be heterozygous for the allele responsible for the grounded trait. If two F1 flies were mated, the percentage of flies that would be expected to be wildtype in the F2 generation would be 25% mutants given that the mutant allele (ap) is predicted to be recessive and, leaving 75% to be wildtype (ap+).
There were eight different phenotypes among the progeny. The highest phenotypic frequency was the w+m+f+ at 40% of the progeny. The lowest was the w+mf+ with only 2 % of the progeny (Table 3). The sum of the recombinant frequencies between genes, table 4, was used to determine the gene distance. The recombinant frequency was determined by counting the number of individuals whose genes differed from that of the parental type. For example, how many individuals white eye gene, and miniature wing gene, differed from both wild-type or both mutants. Recombination occurred between the white and miniature gene 33 times. Recombination occurred between the miniature and the forked genes 31 times. Recombination occurred between the white and forked genes 44 time. Double recombination occurred 10 times. Therefore, genes w and f are 64 m.u. apart, m and w are 33 m.u. apart, and m and f are 31 m.u. apart (Figure
11. The progeny of a Drosophila female (heterozygous at three loci: y, ct, and w) crossed to a wild type male are listed below:
Two sepia virgin drosophila females and five, dumpy drosophila are put in a vial containing agar. Nap was used to anesthetize the flies. After a week f1 had laid eggs and f1 pupas were visible. Parents were removed from vial. A week later the drosophila f1 had developed and were analyzed and counted.
Heterozygotes, which have the wild type phenotype, have normal sight which gives them the advantage of finding a mate and have a better success with attracting a mate with their courtship song (Kyriacou et al, 1978). The male heterozygous Drosophila had a better advantage at mating than the homozygotes, which were the ebony, and therefore we predict there will be more wild type by the end of the experiment.
we said goodbye and placed them in the fly morgue. We allowed the F2 larval
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.
The genus drosophila are fruit flies which over years have had various mutations leading to six different eye phenotypes. These eye colors include: wild (not mutated), white, brown, rosy, scarlet, and sepia. The purpose of this experiment is to understand the mutations that occur during gene expression that causes abnormal protein synthesis and produces a mutated phenotype. The experiment will determine the pigments that are present in each of the mutated eye colors
The vial was then labeled accordingly with the type of cross (Male Vg, Female W) and the date. The date is important as the Drosophila complete a life cycle within approximately 2 weeks from the mating day. This vial became known as the parent generation or (P).
Haplodiploid genetic system is a very curious mechanism in insects. The insects can be either uniparental or biparental, meaning one parent or two. The females can