Identifying unknown phenotypes and determining mechanisms of inheritance of various genes in mutations of Drosophila melanogaster
Michael Fisher, Tori Hall, Lindsey Theodore
Crosses carried out with Drosophila melanogaster can be used to determine mechanisms that modify ratios of Mendelian inheritance, such as autosomal dominant and recessive inheritance, genetic linkage, and epistasis. To identify the eye color phenotypes of two unknowns (U3 and U4), crosses were carried out between the unknowns and flies with known eye color mutations (sepia, white, cinnabar, scarlet, brown, and vermillion) and the F1 generations were observed. Thin layer chromatography was also used to identify the unknowns by showing the pigment composition of each eye
…show more content…
melanogaster is excellent in studying and observing genetic traits, this is due to the flies’ rapid reproduction, numerous offspring, and three chromosome genome.2 Of these three chromosomes, the X chromosome is essential in determining sex, as sex is determined by the ratio of X chromosomes to autosomes in D. melanogaster.2 Male and female D. melanogaster can be distinguished by certain morphology differences. Females are usually larger than males, with stripes along their entire abdomen.3 Males, instead of having stripes at the end of the abdomen, usually have a dark spot at its tip.3 …show more content…
The crosses were set up, and only cinnabar provided offspring that were not wild type leading to the belief that the genotype shown was true cinnabar. Thin layer chromatography
Cross Female Count Male Count Eye Color st ♀ x U3 ♂ 36 25 Brick red st ♂ x U3 ♀ 17 20 Brick red v ♀ x U3 ♂ 3 4 Brick red v ♂ x U3 ♀ 11 7 Brick red cn ♀ x U3 ♂ 16 16 Bright red cn ♂ x U3 ♀ 48 23 Bright red bw ♀ x U4 ♂ 28 19 Brick red bw ♂ x U4 ♀ 36 33 Brick red se ♀ x U4 ♂ 0 2 Brown/Black se ♂ x U4 ♀ 15 26 Brown/Black
also showed similarity’s in the extracts of U3 and cinnabar both being a coral color and also on the plates since similar Rf values were recorded. Between observations of the unknown phenotypes, the crosses run that showed the phenotypes and strong similarities in TLC extracts and Rf values there was a strong case showing U3 as cinnabar and U4 as sepia.
Identifying unknown genotypes using thin layer chromatography
Thin layer chromatography was used as a better gauge of what the unknown phenotypes for U3 and U4 were since extracts and Rf values were observes and recorded for all strains and were shown as distinct in values rather than just being observed as one similar trait of wild type as the crosses had
In this experiment we tested to see what the offspring of an unknown cross of an F1 generation would produce. After observing the F2 generation and recording the data we found some of the Drosophila showed mutations, two in particular. The mutations were the apterus wings, and sepia eyes. After collecting our data through observation, a Chi-test was conducted resulting in a Chi-value of 5.1 and a p-value of .2. Since the p-value was greater than 0.05, there was no significant change in the data. This proved that the Drosophila flies still followed the Mendelian genetics of a 9:3:3:1 ratio.
4. Clear wing, Black eye, and Hairless (c, b, and h) are linked, recessive traits carried on
For one of the monohybrid crosses you performed in this Investigation, describe how to use the phenotype ratios to determine
The goal of this study was to induce a deletion in the DMAP1 gene on chromosome two in Drosophila melanogaster through P-element mobilization. The DMAP1 gene may be an essential gene, however not much is known about it. We attempted to uncover the function of DMAP1 by creating a series of genetic crosses and selecting for brown-eyed non-stubble male flies that may have the deletion. To test whether these flies had the deletion, we produced PCR products and ran them on an agarose gel, which resulted as inconclusive. We created a balanced stock of flies homozygous for the deletion to see if the
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.
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”.
The motivation of this lab report is to use Mendel’s Laws of Inheritance to analyze and predict the genotypes and phenotypes of an offspring generation (F2) after knowing the genotypes and phenotypes of the parent generation (F1). The hypothesis for this experiment is that the mode of inheritance for the shaven bristle allele in flies is autosomal recessive in both male and female flies.
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
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
Genes can either be sex-linked or autosomal. If a gene appears mostly in one sex chances are the gene is sex-linked and if it appears frequently in both sexes it is most likely autosomal. Using Drosophila melanogaster, also known as the fruit fly, we will determine whether the gene is sex-linked or autosomal. Drosophila melanogasters have a relatively short life span and are an excellent organism for genetic studies because it has simple food requirements, occupies little space, is hardy, completes its life cycle in about 12 days at room temperature, produces large numbers of offspring, can be immobilized readily for examination and
Fruit Fly experiment was conducted by using different techniques. One of the main things was to examine the fruit flies and identify the difference between females and males, identify their mutation if they were wild type, white eye, vestigial or white and vestigial combined together. These Fruit flies were kept in the incubator at 25°C for about 6 days. The main goal for this experiment was to observe the principles of Mendelian genetics.
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.
The Drosophila melanogaster is a fruit fly with a very short life cycle. They can be winged or wingless, and have red eyes or white eyes. The different options are called alleles. Alleles are the variants of a specific gene, and one is received from each parent on each chromosome. (“What Are Dominant and Recessive?”). It was chosen to use winged females and wingless males to predict the offspring in this experiment. The winged allele is dominant, meaning it only needs one allele to physically appear. The wingless allele is recessive, which gets covered up by the dominant allele (“Fruit Fly Genetics”). Each trait has two alleles in the flies’
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.
Sex linkage and inherited genes allow us to predict and understand how and why certain animals and plants inherit features from their parents while some don’t. Sex linkage is the condition in which a