tricky F1 cross with specific allele crossover
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tricky F1 cross with specific allele crossover
Ok at first to me this looks like the simple dihybrid cross which is easy to find the resulting f1 generation. All of the f1 will be heterozygotes but when I do the crossover in the problem during meiosis I the gametes that I get do not match the answers to the problem. I attached the file of me drawing meiosis crossing over of allele a and B.

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It cut out my crossover step. I just had an AaBb and AaBb switch a and B
Problem. Parental organisms of genotypes AABB(paternal) and aabb(maternal) were crossed. Then, meiosis occurred in the F1. In one particular meiotic cell in the F1, the chromosome carrying the maternal a allele segregated with the paternal B allele. In this meiosis, there was no crossing over between genes A or B and their centromeres. The gametes resulting from this meiosis are expected to be?
Ok so what i did as seen in the picture is cross two heterozygotes and during crossover only switch a allele with B allele and left the parental chromosome the same. My resulting gametes came out AB Bb Aa ab. THis cant be correct because on this old test question the options are:
1. AB aB Ab ab
2. AB and ab
3. aB and Ab
4. AB Ab
5. aB AB
Am I messing up in the crossover. Thanks for any help! I am going crazy.

Uploaded with ImageShack.us
It cut out my crossover step. I just had an AaBb and AaBb switch a and B
Problem. Parental organisms of genotypes AABB(paternal) and aabb(maternal) were crossed. Then, meiosis occurred in the F1. In one particular meiotic cell in the F1, the chromosome carrying the maternal a allele segregated with the paternal B allele. In this meiosis, there was no crossing over between genes A or B and their centromeres. The gametes resulting from this meiosis are expected to be?
Ok so what i did as seen in the picture is cross two heterozygotes and during crossover only switch a allele with B allele and left the parental chromosome the same. My resulting gametes came out AB Bb Aa ab. THis cant be correct because on this old test question the options are:
1. AB aB Ab ab
2. AB and ab
3. aB and Ab
4. AB Ab
5. aB AB
Am I messing up in the crossover. Thanks for any help! I am going crazy.
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