Drosophila Fruit Flies: A Genetic Analysis

The goal of this study was to induce a deletion in the DMAP1 gene on chromosome two in Drosophila melanogaster through P-element mobilization. The DMAP1 gene may be an essential gene, however not much is known about it. We attempted to uncover the function of DMAP1 by creating a series of genetic crosses and selecting for brown-eyed non-stubble male flies that may have the deletion. To test whether these flies had the deletion, we produced PCR products and ran them on an agarose gel, which resulted as inconclusive. We created a balanced stock of flies homozygous for the deletion to see if the

A) Their F1 offspring were 97 wild type quahaug flies. What is the genotype of these F1 flies??

Drosophila Melanogaster, commonly known as fruit flies, are highly important model organisms in pertaining to biological research. The logic behind their recurrent use is due to their: easy culture in the laboratory, brief generation time, and ability to produce large numbers of offspring. In this report, we created isolated virgin D. Melanogaster from the original three populations we were given and then created crosses between them. Upon observation, we noticed an unusual mutant that arose from two of the three created crosses. We suspected that this genetic mutation had previously been discovered and named.

It would be expected that the mutant F1 flies would be heterozygous for the allele responsible for the grounded trait. If two F1 flies were mated, the percentage of flies that would be expected to be wildtype in the F2 generation would be 25% mutants given that the mutant allele (ap) is predicted to be recessive and, leaving 75% to be wildtype (ap+).

A female fly has to X chromosomes while a male has one X and one Y chromosome. The number of X chromosomes determines the sex as two X’s result in a female and an X and Y result in a male. Genes on these sex chromosomes show sex linkage. In this lab, the difference between the wild type eyes and white eyes is determined by two alleles of that gene on different regions of the X chromosome. In the white eye female fruit flies, there are two X chromosomes, each one having a gene for white-eye color.

Also, a mutant (white eyes and without wings) male is crossed with a virgin wild type female (caramel bodies, red eyes and wings that are oval and folded). Both of these crosses are accomplished in an identical method. The mutant males are sedated utilizing an ether-based product known as fly nap. The vial containing the males is laid on its side. Fly nap is applied to a brush and the brush is inserted into the vial housing the mutant males. The brush is allowed to remain in the vial until all males are sedated. Once sedated the males are carefully removed on to a piece of card stock. At which point the males are carefully introduced to the females vial. The males and females allowed to remain for one week for mating. Week two the parental generation must now be removed to not contaminate the F1 generation. While the F1 generation is still in larva state the parental generation must be removed. This is accomplished by again adding the brush vial and allowing for the sedation of the parental generation. Once the parental generation has been removed and discarded the larva are allow to mature. At week three male and female F1 offspring are crossed to produce the F2 generation. This is again accomplished by sedating the F1 generation with fly nap and sorting males and females apart.

we said goodbye and placed them in the fly morgue. We allowed the F2 larval

The next row(F2 generation), shows us the offspring numbers of a male and female from the F1 generation. Those numbers give us a ratio of 1:1:1:1 of 1 wild male to 1 yellow male to 1 female wild to 1 female yellow. This tells us that there is around the same amount offspring for of each type of fly in the F2 generation.

For our first generation (F1) of flies we chose to cross apterous (+) females and white-eye (w) males. We predicted that the mutation would be sex linked recessive. So if the female was the sex with the mutation then all females would be wild type heterozygous. Heterozygous is a term used when the two genes for a trait are opposite. The males would all be white eye since they only have one X chromosome. If the males were the sex that had the mutation then all the flies would be wild type but the females would be heterozygous.

11. The progeny of a Drosophila female (heterozygous at three loci: y, ct, and w) crossed to a wild type male are listed below:

The vial was then labeled accordingly with the type of cross (Male Vg, Female W) and the date. The date is important as the Drosophila complete a life cycle within approximately 2 weeks from the mating day. This vial became known as the parent generation or (P).

The main purpose for this conducting this experiment was to further knowledge on Mendelian Genetics and how traits are inherited from generation to generation. Something that we attempted to solve was which traits were considered dominant and which were considered to be recessive. Drosophila melanogaster also known as fruit flies were used in this experiment, Dihybrid crosses were done to gather information on how characteristics are linked from generation to generation. Our crosses consisted of female wild type with male sepia eye/ ebony body and female ebony with male vestigial. It is shown that some inheritance patterns are due to unlinked genes and linked genes.

GENETIC CROSSES An “X” is used to indicate that two individuals have been mated together. The parents are designated as P (for parental) and the offspring as F (for filial). When several generations are involved, subscripts are added to designate the generations. P1 give rise to F1 (first filial) progeny. If the F1 are crossed together they become P2 and their progeny F2. A cross between members of the F1 and members of the P1 is a backcross. A cross between members of the F1 and the true breeding recessive P1 is a test cross. MONOHYBRID CROSS The simplest form of a cross is a monohybrid cross, which analyses a single trait and its associated variations. The diagram below shows the

The observed results from the ¬F1 generation were that the phenotypes had to be EeNn x EeNn. The expected results for the F1 generation were also EeNn x EeNn because the P generation phenotypes for the male fruit fly were Ee and were Nn for the female P generation flies. The expected results for the F2 generation were a 9:3:3:1 ratio from the phenotypes NENenEne x NENenEne. The Chi squared value turned out to be 4.14 when the differences between observed and expected results were

If we take S to represent the straight winged insects and a dominant gene and c to represent the curved winged insects. Then you use a punnet square or a test cross. As long as you have the genotypes of the parents then you are good to go. If the alleles of the fly are Sc, then they are heterozygous if its SS then they are homozygous.