Drosophila Autosomal and Sex-Linked Cross
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.
Introduction
Genetics has given us important results with regards to knowing why certain organisms and their expressions are the way they are and how some expressions are suppressed due to those particular expressions being recessive. The reason is because genetics is the study of genes and the effects of it to organisms.
Genes are expected to give offspring hereditary similarities to the parent. However, this was not known and Gregory Mendel asked himself what was passed on by parents to their offspring that is the basis for similarity. Mendel would go on through experiments with pea plants to answer short questions. The answers were short as well as to say that the passing of characteristics from parents to the offspring is throug...
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...e 9:3:4:1 but it did not seem to be significant in the probability.
• Conclusion for class mono-hybrid cross: The p value 0.222 was in the non-significant range in the chi square table. The null hypothesis was therefore correct. The colors of the eyes are sex linked due to the equality in the amount of phenotypes given to both male and female.
• 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.
Bibliography
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The objective of this experiment is to determine what genes are responsible for the white-eye color in two strains of Drosophila melanogaster, known as the common fruit fly. Drosophila is used as the experimental organism for many reasons which include its small size, easy maintenance, short 10 day generation time, and a fully sequenced genome. The characteristics of the wild type, which is the most common phenotype found in nature, include brick red eyes, long wings, gray/tan body, and smooth bristles. Of course, there are mutations that occur that cause specific traits to deviate from the wild-type phenotype. These traits include wing length, bristle shape, body color, and eye color.
Rantala, M. J., and Roff, D. A. 2006. Analysis of the importance of genotypic variation,
Miller, K. R., & Levine, J. S. (2010). Miller & Levine biology. Boston, Mass: Pearson
This meant that we had to reject our hypothesis for the dihybrid cross which stated that there would be no difference in the observed and expected values. This showed that the F2 generations did not follow Mendelian genetics because it did not express a 9:3:3:1 phenotypic ratio. In both our F1 and F2 generations, we had to reject our hypotheses because they did not follow the Mendelian genetic inheritance pattern show by our results above. Because both the F1 and F2 generations of Brassica rapa failed to follow the Mendelian genetics inheritance pattern, there could have been some biological errors that cause this to happen. An example of this is that maybe not every single plant got the exact same amount of water or same amount of sunlight, causing the plants to grow differently and therefore deviate from the Mendelian’s law of inheritance. To prevent this from happening in the future, what could have been done was measure out the amount of water each plant got rather than just watering each plant casually. Also, for the amount of sunlight, steps could have been taken to ensure that each plant would get the exact same amount of light and not get different amounts just because of where they were
revealed that three of the fourteen samples were were homozygous while the other eleven were
1)"Big Idea 2: Cellular Processes: Energy and Communication." AP Biology Investigative Labs: An Inquiry-based Approach. Ed. The College Board. New York: College Board, 2012. 51-61. Print.
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:
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.
In Drosophila (fruit flies) genes can be linked or non-linked. Linked genes are genes that are close together on the chromosome so they often appear in pairs. Non-linked genes are not close together and Mendel’s law of Independent Assortment states that each trait is equally likely to slow up. The purpose of this lab is to find out if the genes of purple eyes and black bodies are linked in Drosophila. Flies are good for this experiment because they display a number of different traits and they mate quickly. If the eye and body color genes are linked in Drosophila then the F2 generation will not have a 9:3:3:1 ratio because the genes are on the same chromosome and cannot independently assort when they are crossing over. Since linked genes often appear in pairs, it is likely that there will be many more flies that are wild-type for both genes or have purple eyes and a black body than a combination of these genes. If the eye and body color genes are not linked in Drosophila then the F2 generation would have a 9:3:3:1 ratio because the law of independent assortment states that each gene has an equal chance of occuring.
This data had a probability of 0.05 according to the chart. The 0.05 probability indicates this data was not very accurate compared to the expected ratio. The female Chi squared was 20.41 which provided a low probability of 0.001. This data was not very accurate at all since the Chi squared was very high and did not follow the ratio closely. The F1 x F1 cross, that used the two parents female sepia and male dumpy, had a male Chi squared of 13.93 which showed a probability of 0.001. The probability showed poor data since it did not fit well with the expected 9:3:3:1 ratio and was lower than the 0.05 cut off. The female Chi squared was 15.13 and showed a probability of 0.001. This data was also not very accurate since it strayed from the expected ratio. Both male and female showed the same expected ratio indicating no different in gender for these genes. The reciprocal crosses also made no impact on the progeny data since the ratios were 9:3:3:1 for both sets of F1 x F1 crosses. Usually it is not a good idea to treat reciprocal test crosses as the same cross using Drosophila because male Drosophila do not cross over while females
The experiment consisted of putting blind mutants (ninaB360d or 1118) in daylight and dark environments to asses their courtship behavior towards intact females and decapitated female flies.
Can we expect that the correlation between CNP genotypes (hybridization intensities) and CNP phenotypes is reasonably high?... ... middle of paper ... ...10) Line 158, In case the copy number is the same (c=b), the equation would give zero. Is this the right one? 11) Line 171, SNP phenotypes -> CNP phenotypes?
A fly with just the “promoter-Gal4” is known as the driver line. The “UAS-GFP” alone in fly allows us to determine what specific foreign gene is introduced into the fruit fly’s genetic makeup. In this case, the “UAS-GFP” alone in flies allows us to determine that GFP is the incorporated foreign gene into the fruit flies genome, but it is not actively expressed. A fly with just the “ UAS-GFP” in known as the responder line. This allows for the crossing over of both lines of flies to show an expression of a specific gene at a specific tissue in their offspring and this allows to determine the effects of both components in the fruit
more than half the variation was found to be due to heredity. Among these traits were
Quantitative genetics consists of constantly changing characters. From the name of quantitative genetics, it pursues to ‘quantify’ changes in the frequency distribution of traits that cannot simply be located in discrete phenotypic classes (Falconer, D.S. 1996). Upon analysis of the future of quantitative genetics being relevant in this age of rapid advancement in molecular genetics, it has been useful to evolutionary biology which quantitative genetics has been allocated a major boost from the extensive effort/work of Lande-which portrays how the actual equations of quantitative genetics can be extended and used to solve situations beyond livestock and the improvements of crops. In the activities of quantitative genetics in this age, there seems to be a risk in quantitative genetics falling on rough times, having being known as the ‘old’ way of molecular genetics or ‘The out-moded’ as opposed to the comparison of the new types/areas of molecular genetics of today’s age and era. The intention is to bring awareness of the importance of the use of quantitative genetics and placing it in proper perspective. As well as to target the amazing successes, especially central questions of evolutionary biology that can only be statistically answered fully via the requirement of a quantitative genetic perspective. Although through the quantitative genetics theory, the ability and availability to take into consideration the inheritance of quantitative traits such as fertility, the body size, etc is of high importance. Quantitative genetics is also an important contribution to the understanding of inbreeding depression which is the reduced productiveness of the offspring of closely related individuals. The counter-intuitive outcome of quantita...