A common fruit fly, Drosophila melanogaster, was used in the experiment to determine the mode of inheritance of the apterous mutant flies over several generations. The possible modes of inheritance could have been autosomal or X-linked and dominant or recessive. It was predicated that the apterous Drosophila flies were autosomal recessive, hence evaluated using reciprocal monohybrid crosses. The F1 and F2 generations were observed and compared to the hypothesis. An analysis of the F2 generation was performed through chi-square analysis. Although, there was an error, the mutation was most likely autosomal recessive.
Drosophila melanogaster, a type of fruit fly, is most commonly found in the wild, but also a great model organism in the laboratory. …show more content…
If there are two X’s it is a female whereas, if there is one X and a Y, it is a male. The female flies are larger than the males as well as have a pointed abdomen rather than round. A gene is a heredity unit, thus made up of DNA (King & Stansfield, 1985, p.151). Two alleles are inherited from each gene, hence, if homozygous, the alleles are the same, and if heterozygous, the alleles are different (King & Stansfield, 1985, p.14). The mode of inheritance is determined through experimental crosses to identify if the mutation is autosomal or X-linked, and also dominant or recessive. An autosomal mutation is any chromosome other than the sex-determining chromosome (Pagon et al., 2015). If Drosophila were to be identified as X-linked, the X chromosome would have a gene present (King & Stansfield, 1985, p.419). A dominant mutation produces a wild-type phenotype when the allele is present. Likewise, if there is an absence in an allele, the mutant phenotype is produced, representing a recessive mutation (King & Stansfield, 1985, p.331). Evolutionary factors are most likely the same in autosomal and X-linked genes, with the exception of differences between the two groups of loci (Hedrick & Parker, 1997). Autosomal dominant would consist of only one mutated copy, whereas an autosomal recessive inheritance would have two mutated copies of the …show more content…
Even though there were some mutants in the F1 generation, majority of the flies wild-type. Therefore, mutants are not dominant because the mutation was not seen in the F1 or it was a very small percentage. The F1 generation is also not X-linked because if it was, all the males would be mutant, therefore, by default, the mutation is most likely autosomal. Overall, the outcomes of the F1 generation were as estimated to be a 1:0 ratio. Similarly, the F2 generation also resulted in expressing the autosomal recessive mutation, but the percentages of offspring were distributed. The mutants are recessive in the F2 generation because the number of wild-type flies is greater. The F2 generation did not demonstrate the predicted 3:1 ratio, but instead a 5.04:1 and 10.7:1 ratio. The mutation is considered to be recessive, but the distribution that was expected is supported by the chi-square analysis and the small p values. The χ2 analysis was a “poor fit” for both of the crosses because of possible experimental
Drosophila melanogaster, a type of fruit fly, is most commonly found in the wild, but also a great model organism in the laboratory. …show more content…
If there are two X’s it is a female whereas, if there is one X and a Y, it is a male. The female flies are larger than the males as well as have a pointed abdomen rather than round. A gene is a heredity unit, thus made up of DNA (King & Stansfield, 1985, p.151). Two alleles are inherited from each gene, hence, if homozygous, the alleles are the same, and if heterozygous, the alleles are different (King & Stansfield, 1985, p.14). The mode of inheritance is determined through experimental crosses to identify if the mutation is autosomal or X-linked, and also dominant or recessive. An autosomal mutation is any chromosome other than the sex-determining chromosome (Pagon et al., 2015). If Drosophila were to be identified as X-linked, the X chromosome would have a gene present (King & Stansfield, 1985, p.419). A dominant mutation produces a wild-type phenotype when the allele is present. Likewise, if there is an absence in an allele, the mutant phenotype is produced, representing a recessive mutation (King & Stansfield, 1985, p.331). Evolutionary factors are most likely the same in autosomal and X-linked genes, with the exception of differences between the two groups of loci (Hedrick & Parker, 1997). Autosomal dominant would consist of only one mutated copy, whereas an autosomal recessive inheritance would have two mutated copies of the …show more content…
Even though there were some mutants in the F1 generation, majority of the flies wild-type. Therefore, mutants are not dominant because the mutation was not seen in the F1 or it was a very small percentage. The F1 generation is also not X-linked because if it was, all the males would be mutant, therefore, by default, the mutation is most likely autosomal. Overall, the outcomes of the F1 generation were as estimated to be a 1:0 ratio. Similarly, the F2 generation also resulted in expressing the autosomal recessive mutation, but the percentages of offspring were distributed. The mutants are recessive in the F2 generation because the number of wild-type flies is greater. The F2 generation did not demonstrate the predicted 3:1 ratio, but instead a 5.04:1 and 10.7:1 ratio. The mutation is considered to be recessive, but the distribution that was expected is supported by the chi-square analysis and the small p values. The χ2 analysis was a “poor fit” for both of the crosses because of possible experimental