Question

A gamete affected by non-disjunction would have

• A. The potential for a genetic disorder
• B. One extra or one missing chromosome
• C. Change from the normal chromosome number
• D. All of the above
  

Answer 1

Answer: (D)

All of the above

• Nondisjunction can occur either during meiosis I or meiosis II, but it is more common during meiosis I. If nondisjunction occurs, then the gametes will not contain the correct number of chromosomes; instead of a single copy, the gametes will either have two copies of a chromosome or no copies.
• Nondisjunction disorders are when cell division development of the zygote has an imbalanced amount of genetic information. This imbalance affects the distribution of the chromosomes or genetic information that each cell has. Having abnormal amounts of karyotypes in the chromosomes will overload the cells and this in turn can kill the zygote or in some cases, a person with Nondisjunction disorder is born.

For example: Down Syndrome

The result of an extra copy of chromosome 21. Down syndrome affects 1:700 children and alters the child's phenotype either moderately or severely. These people can have heart defects, short stature, susceptibility to respiratory disease, shorter then average lifespan, can develop Alzheimer's and leukaemia easier.

So, the correct answer is 'All of the above'.