Morgan's Experiment


Morgan choose Drosophila melanogaster for his experiment due to some important reasons:

  • He noticed that a white-eyed male drosophila instead of the regular red eyes.
  • Size of the drosophila was small.
  • They have a short lifespan, therefore so many generations can be studied in a short time frame.
  • Drosophia’s have a high reproduction rate.

Morgan crossed a pure-bred white eyed male with pure-bred red-eyed female drosophila. As expected following the Mendel’s laws, the F1 progeny were born with red eyes. When F1 generation was crossed among each other, ratio of red-eyed to white eyed progeny were 3:1. However, Morgan noticed that there was no white- eyed female in the F2 generation.

To understand further Morgan performed a cross between a heterozygous red-eyed female with a white-eyed male. This gave a ratio of 1:1:1:1 in the progeny (white eyed female:red eyed female: white eyed male: red eyed male). This experiment made Morgan to think about the linkage between the traits and sex chromosomes. He performed many cross experiments and identified that the gene is responsible for the eye color which was situated on the X chromosome.

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