RESULTS
Table 1: Phenotypes of F1 flies produced by crossing wild-type females and no-winged males. Females Males Total
Wild-Type 47 53 100
No -winged Mutant 0 0 0
Table 1 shows the phenotypes of the F1 flies produced by crossing P1 wild-type females and P1 no-winged mutant males. The results of that cross was that there were forty seven wild-type females and fifty three wild-type males. Therefore there was a total of one hundred wild-type flies that were produced. The observed phenotypic ratio of wild-type flies and no-winged mutant flies was 1:0 (wild-type: no-winged). The predicted phenotypic ratio if the no-winged mutation is autosomal recessive would be 1:0 (winged: no-winged).
Table 2: Phenotypes of F1 flies produced by crossing wild-type males and no-winged females. Females Males Total
Wild-Type 59 41 100
No-winged Mutant 0 0 0
Table 2 shows the phenotypes of the F1 flies produced by crossing P1 wild-type males and P1 no-winged females. The results of that cross was that there was fifty nine wild-type females and forty one males. Therefore there was a total of one hundred wild-type flies produced from crossing P1 true breeding wild-type males and P1 true breeding virgin
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The results of this cross was that there were thirty eight wild-type females and thirty five wild-type males. Therefore there were seventy three wild-type flies. There were sixteen no-winged mutant males and eleven no-winged mutant females. Therefore there was a total of twenty seven no-winged flies produced in this cross. The observed phenotypic ratio of wild-type flies and no-winged mutant flies was 2.7:1 (winged: no-winged).The predicted phenotypic ratio if the no-winged mutation was autosomal recessive would be 3:1 (winged: no-winged). The χ2 value obtained for this cross was 0.213. The p value that was obtained for this cross was
Thus, the genotype of a wild-type homozygote would be designated e +e + (or ++), a mutant homozygote ee, and a heterozygote e +e or e+ [Use of the term “wild-type” derives from an early assumption that most flies are homozygous for a ‘standard’, usually dominant, allele. As we will see, this is not the case, but the terminology is still used]. It is important to remember that not all mutants are recessive. A mutation that is dominant to the wild-type is symbolized by a capital letter. For example, the typical eye shape is round. One mutant produces a narrow “bar eye”: the allele is dominant, symbolized by a capital letter B, and the wild-type (round) eye is B+.
A) Their F1 offspring were 97 wild type quahaug flies. What is the genotype of these F1 flies??
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.
It was decided that there would be 80 vestigial flies and 20 wild type flies to total to an initial population of 100 drosophila. Next, the flies were anesthetized flies using Fly Nap. The flies were counted out to reach desired ratio, sexing the flies making sure there are equal amounts of males and females to be sure there is ample individuals to allow successful mating. The fly’s food was prepared by taking a frozen rotten banana, cutting it in half, mashing up the banana meat, and mixing yeast into it. The
We started out with three populations; B, D, and G. In order for us to properly create controlled genetic crosses, we had to ensure that all the female flies were “virgins”.
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+).
Steps 7-11 were repeated to record the phenotype of the F2 generation and number of male or female flies.
11. The progeny of a Drosophila female (heterozygous at three loci: y, ct, and w) crossed to a wild type male are listed below:
The fruit flies were provided on March 27,2018. The fruit flies were incubated at 25°C for a couple of days. On April 3,2018 the F1 generation was examined which allowed to figure out the P generation by setting up crosses and collecting data. On April 10,2018 the identification, separation and counting of phenotypes in F2 generation was completed. On April 10, 2018 the fruit flies had to be counted correctly according to their phenotypes. Counting the sex of the fruit flies and analyzing for any specific mutation. On April 17,2018, F2 generation was counted and by that information that was obtained, a Chi-square test was made in order to prove or disapprove the hypothesis. Lastly, fruit flies were then removed from the cultured vials with larva and eggs and were placed in a sleeping chamber in order for the F1 generation to be counted and observed under the microscope. The reason why they had to be counted was to identify the sex and the phenotype from each individual fly. Then, the data was analyzed after the flies were counted, and a chi-square test was conducted. Since six vials were obtained from the instructor, two of the group members had to count 2 vials of F1 as well as F2 the other two members only had to count the fruit flies of one
This determination was mainly so the group could easily spot the sex and traits of the flies for later steps. This was done to all four tubes of the P generation, all of the adult females were placed disposed of roughly 30 males from the wild type were kept in a separate jar. The adult females were not wanted because the females could have already mated with the males and the group needed the control of the transfer of genetics for the test crosses. The new virgins were born and collected approximately eight hour after the removal of the adults and placed into separate jars labeled by the genotype of their parents. After the process was done and 5-6 virgin females were collected the process could continue in order to cross still the P generation.
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.
This experiment looks at the relationship between genes, generations of a population and if genes are carried from one generation to another. By studying Drosophila melanogaster, starting with a parent group we crossed a variety of flies and observe the characteristics of the F1 generation. We then concluded that sex-linked genes and autosomal genes could indeed be traced through from the parent generation to the F1 generation.
For each pair of traits crossed, one alternative was not expressed in the F1 hybrids, although it reappeared in some F2 individuals