Sunday, August 22, 2010

How did Thomas Hunt Morgan determine that eye color in Drosophilia is an X-linked trait?

How did Thomas Hunt Morgan determine that eye color in Drosophilia is an X-linked trait?











please help me with this question.





this is the answer i put: he crossed a white-eyed male with a red-eyed female and his predictions came out as planned -- the whole F1 generation came out with red eyes.





i got it marked wrong though.





but i still need to know the answer for the test tomorrow.


thanks to everyone that helped me out.





please briefly explain your answer in no more than 2 sentences.





once again thank you!

How did Thomas Hunt Morgan determine that eye color in Drosophilia is an X-linked trait?
The first generation (the F1) produced 1,237 red-eyed offspring and three white-eyed males. The second generation (the F2) produced 2,459 red-eyed females, 1,011 red-eyed males, and 782 white-eyed males.
Reply:He observed psuedodominance, whereby the mutation that was on the X chromosome acted in a dominant fashion in the male who only has one X chromosome. The female has two X chromosomes, so in the F2 generation if the trait is sex-linked and recessive in nature then no females and half the males will have the normal phenotype while half the males will have the recessive white eyed phenotype.


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