Inheritance Patterns

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

1 by crossing over in prophase I , 2 , by indpendenent assortment and three by mutations in S phase

Apply your understanding of how alleles assort and combine during reproduction to evaluate a scenario involving a monohybrid cross.

Part B: Genes X, Y, and Z are linked. Crossover gametes between genes X and Y are observed

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.

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.

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.

This discovery was made when Morgan was working at Columbia and one day, while observing a male fruit fly, he noticed that instead having bright red eyes as any normal Drosophila melanogaster would, this particular insect had white eyes. Morgan questioned the cause of the color of that fly to be different and wondered how this trait was acquired. In order to answer his questions, Morgan proceeded to do simple breeding analyses with the white-eye fruit fly. This experiment began with a test cross between the white-eyed fly with normal red-eyed females. The results in the first generation was all red eyes. This was shown through the use of Punnett squares. However Morgan didn’t stop there, he took the male and females from the first generation and test crossed them again. This time, the second generation resulted with some flies with the white-eyed trait along with some red-eyed trait. Morgan noticed that the only white-eyed trait however occurred only in the male fruit flies. This led to his hypothesis of sex-limited, also known as sex-linked. However, upon further experimentations, the next generations of crossing the original male with some first generation red-eyed females resulted with both red-eyed and white-eyed males and females, therefore the trait was concluded to be sex-related and the trait of the coloured-eyed gene was found to be on the X-chromosome. Thus the discovery of how genes are transmitted through chromosomes. In 1933, Thomas Morgan

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

Based upon observation of the F1 generation, we hypothesize that the inheritance of the white-eye (W) mutation is sex-linked and recessive wild type.

The techniques that I used during our session were ABCDE model, scaling, miracle question, and inheritance chaining. The scaling question was supposed to be used at the beginning of our session to grasp an understanding of how the client felt and where to discuss the situation properly. The ABCDE model was used to see what the activating event was and to dispute any irrational beliefs that my client had. Inheritance chaining tied in with the ABCDE model because is continues with “what’s the worst that could happen?” In which my client pinpoint that the copies were still completed for the main purpose, even though they weren’t done his/her way.

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.

The pairs of alternative traits examined segregated among the progeny of a particular cross, some individuals exhibiting one traits, some the other