1. Drosophila melanogaster has been used as a model organism to study human genetics because: it shares 75% homology with human diseases causing genes. Developmental genes are highly conserved in humans and Drosophila. Certain mutations can affect the same tissue in both the fly and human. Example of homologous genes includes: Hox gene, PAX 6, SALL1, TWIST 1, NKX2-5. Drosophila offers several other advantages that makes it an ideal organism for genetic diseases. The fly is easy to maintain and manipulate. It produces a large number of offspring’s and has a short generation interval that is very favorable in genetic studies. The genetic information of the fly codes for 13600 proteins, most of which have functional homology to human proteins (Chen, Wang, Tu, & Huang, 2016). Thus, research on the fly can offer insight into the biological functions of human genes. It is easy to create mutations in the fly and also back cross progenies for genetic studies. Genetic manipulation of human genes is not feasible and not ethical. (Bier, 2005)
2. The wild type Drosophila flies have red eye colored. On the other hand, white eye colored flies evolved from genetic variations in genes that code for eye color (Heil et al., 2012). In order to study the gene for eye color, white eyed flies were crossed with wild type red eyed flies. All the F1 progenies resulting from the cross had red eyes. When F1 progenies were test crossed with the white eyed parental phenotype. It resulted in four different eye color: red, bright red, brown and white in 1: 1: 1: 1 ratio. When the initial F1 red eyes progenies were crossed among themselves; it again resulted in 4 different progenies: red, bright red, brown and white. However, a majority were red, followed by bright red, fewer were brown and even fewer were white eyed. The approximate ratio of the F1 cross was in the direction of 9:3:3:1, which suggest a dihybrid cross. ("Genetics Unit", 2016)
References:
Bier, E. (2005). Drosophila, the golden bug, emerges as a tool for human genetics. Nat Rev Genet, 6(1), 9-23. http://dx.doi.org/10.1038/nrg1503
Chen, B., Wang, X., Tu, Z., & Huang, Y. (2016). Leap forward with insect genomics. Insect Science. http://dx.doi.org/10.1111/1744-7917.12355
Heil, C., Hunter, M., Noor, J., Miglia, K., Manzano-Winkler, B., McDermott, S., & Noor, M. (2012). Witnessing Phenotypic and Molecular Evolution in the Fruit Fly. Evolution: Education and Outreach, 5(4), 629-634. http://dx.doi.org/10.1007/s12052-012-0447-5
Genetics Unit. (2016). Indiana.edu. Retrieved 6 May 2016, from http://www.indiana.edu/~oso/lessons/Genetics/bw_st.html
