Solom813
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Hi please can someone help me with this. I’ve done the cross but I’m stuck on the question below

Eye colour and body colour are linked genes in Drosophila fruit flies.

• Red eyes (R) are dominant over white eyes (r)
• Tan body colour (T) is dominant over yellow (t)


Assume red eyes are linked with tan body colour and white eyes are linked with yellow body colour

Cross a homozygous red eyed, tan bodied parent with a homozygous white eyed, yellow bodied parent. Assume crossing over has not happened.


If crossing over had happened in the cross above, would you expect to see any recombinant phenotypes? Explain your answer.
Last edited by Solom813; 3 months ago
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Juneptpt
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(Original post by Solom813)
Hi please can someone help me with this. I’ve done the cross but I’m stuck on the question below

Eye colour and body colour are linked genes in Drosophila fruit flies.

• Red eyes (R) are dominant over white eyes (r)
• Tan body colour (T) is dominant over yellow (t)


Assume red eyes are linked with tan body colour and white eyes are linked with yellow body colour

Cross a homozygous red eyed, tan bodied parent with a homozygous white eyed, yellow bodied parent. Assume crossing over has not happened.


If crossing over had happened in the cross above, would you expect to see any recombinant phenotypes? Explain your answer
Which part of the question specifically are you stuck on? Do you know what crossing over and recombinant phenotypes are?
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Solom813
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(Original post by Juneptpt)
Which part of the question specifically are you stuck on? Do you know what crossing over and recombinant phenotypes are?
No not really
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Juneptpt
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(Original post by Solom813)
No not really
Ok, well crossing over happens during meiosis, pairs of homologous chromosomes line up next to each other, and genetic material is swapped between them. The product of this is a recombinant chromosome.

So, a recombinant genotype in your question could be Red eyes and yellow body, or white eyes and tan body.
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Solom813
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(Original post by Juneptpt)
Ok, well crossing over happens during meiosis, pairs of homologous chromosomes line up next to each other, and genetic material is swapped between them. The product of this is a recombinant chromosome.

So, a recombinant genotype in your question could be Red eyes and yellow body, or white eyes and tan body.
Oh ok
So would the answer be yes
How do I explain why
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Juneptpt
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(Original post by Solom813)
Oh ok
So would the answer be yes
How do I explain why
Yes, you would expect to see recombinant genotypes. To explain why, I would explain the process of crossing over in meiosis, leading to recombinant chromosomes. I recommend watching youtube videos to help with your understanding and to visualise it.
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