(Start with drosophila as a model organism)
Drosophila melanogaster (D. melanogaster), the fruit fly, has proven to be an invaluable model organism that’s been used to study many genetic phenomena, including X-linked inheritance, gene mapping, and autosomal inheritance . D. melanogaster has been used as a model organism for over 100 years, and its genome (containing ~14,000 genes) has been well-studied, thus making it ideal as a model organism. As with most of the long-established model organisms, practicality is key. D. melanogaster has a simple diet, and the life cycle is relatively short, so large-scale crosses can be followed through many generations .
(How drosophila will be used in crosses)
As previously mentioned, D. melanogaster has been used extensively in genetic studies, which is what we plan to utilize them for in our lab. There are many ways that fruit fly DNA can be mutated to create visible traits, called phenotypes . In our lab, we used the strains lobe, eyeless, sepia, white, and wild-type, we to performed crosses and reciprocal crosses to determine if the corresponding phenotypes were autosomal-linked or X-linked traits. The Lobe strain exhibits a smaller eye than wild-type, caused by a mutation in the optic lobe of the brain. The eyeless mutation makes it so D. melanogaster does not make eyes during development . Lastly, the sepia strain of D. melanogaster exhibits a sepia pigment in the eyes of the organism , while white strain has a deletion of genes responsible for making the red pigment observed in wild-type eyes, so appear white. It should be noted that the white mutation is located on the sex chromosome, meaning males and females have different numbers of copies of this gene.  By utilizing these crosses and examining the F1 generation phenotypes, we should be able to label each strain successfully and use the knowledge gained from the crosses in future work.
(Touch on meiosis, as it’s required for genetically nonidentical gametes for crosses)
Meiosis is an important player in drosophila genetics and one reason drosophila is an excellent model organism for studying genetics. Many other model organisms, such as C. elegans, are hermaphroditic and produce genetic “clones” of themselves, and therefore are not as suitable for studying genetics as drosophila, which undergo sexual reproduction: meiosis. The process of meiosis produces four genetically unique cells, each with half of the number of chromosomes as in the parent . ...