Drosophila Fruit Flies

The fruit fly Drosophila melanogaster are an excellent specimen for research in genetics. Many reasons are that they have a rapid reproduction rate, easy to care compared other animals and less expensive. Researchers have determined the nucleotide sequence of nearly the entire 120 megabase euchromatic portion of the Drosophila genome (Cite). Drosophila has a simple genetic arrangement of only four chromosomes which contains three autosomes and one sex chromosome according to(--) and because of this are commonly used in genetic research. The roles fruit flies play in genetics also help the understanding of genetics in humans and other animals. Drosophila fruit flies share about seventy percent of the genes that cause disease with humans so
that scientists can use them as a genetic model for several human diseases including Parkinson’s and Alzheimer’s. Once females and males mate, the females are capable of laying several eggs, which will go through the larva and pupal phases to develop into adults in a couple of days. Fruit flies can be found en anywhere, typically where food is decomposing. The Normal adult fruit flies normally have red eyes and are between3 to 4 mm in length.
The core of simple inheritance patterns is Mendelian genetics.
Its founder Gregory Mendel based it on three laws. The Law of Independent Assortment states that genes for different traits can independently separate during the development of gametes. The Law of Segregation which is each gene separates during gamete formation so that each gamete transfers only one allele of each gene. The last one is Law of Dominance which states that some alleles are dominant others are recessive and that an organism with at least one dominant will show the phenotype or the result of that dominant allele. The main test crosses used are a monohybrid cross and dihybrid cross. Monohybrid meaning “one” is the simplest mating between true-breeding individuals from two parental organisms, each displaying one of the two distinct traits of the solo trait under consideration. A dihybrid cross is when two pairs of contrasting traits are studied at the same. Both crosses produce distinctive phenotypic ratios in the second generation (F2) of an offspring. The second generation, a monohybrid cross usually shows a 3:1 phenotypic ratio and a dihybrid cross preferably shows a 9:3:3:1 phenotypic ratio. This specific fruit fly breeding study is essential because its results may provide evidence for simple patterns of Mendelian inheritance (Klug, Cummings, Spencer, Palladino 36,
39).
The purpose of this research is to decide if our second generation (F2) of offspring will agree with the projected phenotypic ratios according to Mendelian genetics.
Our hypothesis was that our crosses of a sepia ♀ x apertous ♂ will reproduce the predicted phenotypic ratio for a monohybrid cross according to Mendelian genetics. For that reason, we expected that if the inheritance patterns for a monohybrid cross according to Mendel are correct, then we would see a 3:1 relation of apertous flies to sepia flies in the F2 generation. In this study, we will cross two P1 true-breeding strains of sepia ♀ x apertous ♂ fruit fly parents to produce the F1 generation offspring. Then cross the F1 generation to produce the F2 offspring. The F1 and F2 offspring will be counted to conclude if their phenotypes match with the expected
ratios.
Bibliography
Klug, William S., Michael R. Cummings, Charlotte A. Spencer, and Michael A. Palladino. Essentials of Genetics. Pearson. 2013. Print.
Mark, Adams., Susan, Celniker., Robert, Holt (2000-03-24). "The Genome Sequence of Drosophila melanogaster”. Vol. 287 no. 5461. Retrieved 2010-11-26.