What would be the main problem with reproduction if meiosis did not take place to form sex cells?

Question

The zygote would have two nuclei.
Fertilization would result in a zygote with half as many chromosomes as the parents.
Fertilization would result in a zygote with twice as many chromosomes as the parents.
The zygote would have no nucleus.

Answer 1

If meiosis did not take place to form sex cells (gametes), the main problem with reproduction would be that fertilization would result in a zygote with twice as many chromosomes as the parents.

Here’s why:

• Meiosis is a process that reduces the chromosome number by half, resulting in haploid gametes (for example, sperm and egg cells in animals).
• When two haploid gametes fuse during fertilization, they create a diploid zygote with a chromosome number that is the sum of the chromosomes from both parents.
• If meiosis did not occur and instead the gametes were produced through mitosis, then the gametes would retain the diploid chromosome number. Fertilization of two diploid gametes would lead to a zygote with a chromosome number that is double that of the parents, causing chromosomal imbalances and likely resulting in developmental issues or inviability of the zygote.