Reciprocal crosses and inheritance patterns in Drosophila melanogaster

Drosophila Lab Report

During the Mendel's rule in 1900, Drosophila melanogaster became a favorite model organism for genetics research. The life cycle of the fruit flies or Drosophila melanogaster, consists of the egg-larva-pupa-adult (male and female). The chromosomes are detailed structurally in comparison to the other normal chromosomes. The chromosomes also have the capacity to show during interphase when normal chromosomes are invisible. The main objective of this experiment is to oversee setup of reciprocal crosses with pure-breeding males and virgin females in relation to the application of Drosophila melanogaster.

Following the rediscovery of the Mendel's rule in 1900, Drosophila melanogaster became a favorite model organism for genetics research. The model (fruit fly) enhanced its popularity among the genetic researchers because of several reasons. One of the essential reasons for its popularity is because of the essence of small flies with increased rearing abilities within the context of the laboratories. This is essential for realization of the goals and objectives of the researchers in the execution of the experiments. The fruit flies also have a short life cycle. This is an indication that adult flies can be obtained every two weeks thus effective for the execution of genetic research exercises (Capy et al., 2006).

The life cycle of the fruit flies or Drosophila melanogaster, consists of the egg-larva-pupa-adult (male and female). Another essence of popularity for this model in the context of genetic research is that the fruit flies or Drosophila melanogaster are fecund. This is based on the capacity of the female to lay hundred of fertilized eggs in the course of the brief life span (Capy et al., 2006). The resulting population is essential for execution of easy and reliable statistical analysis during the execution of the experiment.

Another aspect of popularity is the concept of the giant chromosomes within the salivary glands of the mature larvae. The chromosomes are detailed structurally in comparison to the other normal chromosomes. The chromosomes also have the capacity to show during interphase when normal chromosomes are invisible. The embryo also grows outside the body thus facilitating effective study at each stage of development. There is also the possibility of targeting mutations in relation to specific genes. The genome is relatively small thus essential for execution of a reliable and credible statistical analysis (Capy et al., 2006).

Overview of the Experiment

The main objective of this experiment is to oversee setup of reciprocal crosses with pure-breeding males and virgin females in relation to the application of Drosophila melanogaster. The project focuses on the application of a pair of reciprocal crosses in the form of monohybrid and di-hybrid crosses. The experiment seeks to adopt wild-type flies and flies with white eyes, yellow bodies, or abnormal antennae to facilitate the goals and objectives of the concept of monohybrid crosses. In this cross, the focus will include mutant females and wild-type males while the other will be the opposite of the initial cross. The focus of this group is on the antennapenia cross of wild type (male antennapedia x female wt & male wt female antennapedia).

54 ant males

In the first aspect of crossing focusing on the E1 data, there were 46 wild-type females and 58 wild-type females in the second crossing. This was aided with the aspect of 48 wild-type males in the first crossing and 33 wild-type males in the second crossing. The first crossing focuses on the crossing between antennapedia female and wild type males. The second crossing focuses on the crossing of the wild type females and antennapedia males. According to the results of the first bottle in the context of the F1 data, (first crossing), the outcome illustrates 46 wild type females and 48 wild type males. The data also illustrates the concept of 36 antennapedia females in comparison to 35 antennapedia males. In the second crossing within the context of the F1 data, the outcome illustrates 58 wild type females in comparison to 33 wild type males. The data also indicates the outcome of 33 antennapedia females and 15 antennapedia males. In the second bottle (F2 crossing), the outcome illustrates 101 wild type females and 106 wild type males. The data also illustrates the concept of 58 antennapedia females in comparison to52 antennapedia males. In the second crossing within the context of the F2 data, the outcome illustrates 96 wild type females in comparison to 91 wild type males. The data also indicates the outcome of 62 antennapedia females and 54 antennapedia males.

Discussion

According to the results of the first crossing, mutations of the wild type females are dominant over the genes of the wild type males. This is essential in the outcome of the large number of antennapedia wild type females and males. The dominant mutation in this context of crossing is illustrated through A+. In the second crossing in relation to the F1 crossing, the dominant gene is the X chromosomes of the antennapedia wild type males. This is essential in the illustration of the outcome of the crossing with the essence of various antennapedia flies with reference to the results as indicated in the F2 table or data. The two sets of data are applicable in the examination of the frequency of different types of double exchanges.

The results from this experiment confirm the essence of relative frequencies of two and four strand double exchanges. There is no existing assumption in relation to the 1:1 ratio for the crossing with reference to F1 and F2 crossing within the context of this experiment. Detected double crossovers refer to the reciprocal rightmost crossover in the form of ba/ab offers a means for the evaluation and comparison of the frequencies of the two and three strand double exchanges. According to the data, it is essential to note that the two stand double exchange occurs in reference to the expected proportions despite the fact of the existence of limited certainty to the occurrences (Capy et al., 2006).

In this experiment, female heterozygous in relation to the closed X chromosome is essential in the demonstration of the relationship within the two and four strands double exchanges. It is essential to note that homozygosis in relation to any locus in the context of the attached X chromosomes reflects a function of the crossing over between the locus and the spindle attachment. This is vital in the illustration of the data and the crossing of the fruit flies with reference to the dominant and the recessive genes (Capy et al., 2006). From this perspective, antennapedia is an illustration of the dominant gene and chromosome thus the reflection of the outcome of the F1 and F2 crossing with reference to the achievement of the objective of the experiment.

This experiment is a reflection of a foundation to the realization of the concepts focusing on the crossing of the fruit flies. It is essential for the execution of further research with similar parameters. This will provide the opportunity to enhance and focus on the findings of the experiment executed with reference to antennapedia while focusing on the wild type males and females. Further researchers will also address limitations of this experiment while focusing on expanding the scope of the research study. This is beneficial for the understanding of the concepts and perspectives in accordance with the directives of the model in studying genetic research.

Conclusion

Drosophila melanogaster model is a reflection of a popular model in the context of understanding and evaluating essence of genetic study. The model is popular and common in the analysis of genetic research because of various reasons. Some of the reasons for popularity of the model include high population for reliable and credible analysis, short life cycle of the fruit flies, small genome, and high capacity for rearing within the lab (Capy et al., 2006). The main objective of this laboratory exercise was to execute an effective crossing between the wild type males and females with the dominant gene as antennapedia.

Reference

Capy, P., Gibert, P., & Boussy, I. (2004). Drosophila melanogaster, Drosophila simulans: So similar, so different. Boston: Kluwer Academic.