Problem: Imagine that a human primary oocyte undergoes the first meiotic division but experiences a nondisjunction event such that both copies of chromosome 7 are transmitted to the first polar body and neither are inherited by the secondary oocyte. Oogenesis is then completed and the resulting egg is fertilized by a healthy sperm with normal chromosomal content. a. How many chromosomes will be present in the resulting zygote?b. Would you describe this zygote as haploid, diploid, polyploid, or aneuploid? c. Would you expect this nondisjunction event to result in substantial phenotypic effects on the resulting offspring or would the outcome be more or less the same as if the nondisjunction event had not occurred?

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FREE Expert Solution

a. Given that the secondary oocyte contains only 22 chromosome and will be fertilized with a sperm with 23 chromosomes, the resulting zygote will have 45 chromosomes.

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Problem Details

Imagine that a human primary oocyte undergoes the first meiotic division but experiences a nondisjunction event such that both copies of chromosome 7 are transmitted to the first polar body and neither are inherited by the secondary oocyte. Oogenesis is then completed and the resulting egg is fertilized by a healthy sperm with normal chromosomal content. 


a. How many chromosomes will be present in the resulting zygote?

b. Would you describe this zygote as haploid, diploid, polyploid, or aneuploid? 

c. Would you expect this nondisjunction event to result in substantial phenotypic effects on the resulting offspring or would the outcome be more or less the same as if the nondisjunction event had not occurred?

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Chromosome Abnormalities and Non-Mendelian Inheritance concept. You can view video lessons to learn Chromosome Abnormalities and Non-Mendelian Inheritance. Or if you need more Chromosome Abnormalities and Non-Mendelian Inheritance practice, you can also practice Chromosome Abnormalities and Non-Mendelian Inheritance practice problems.

What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Arthun's class at CSU.