how many chromosomes do normal mice zygotes contain?
There should be 23 tetrads in a human cell at the beginning of meiosis. The cell then divides twice with the chromatids separating each time. This results in four cells each of which contains 23 chromosomes (46/2). These cells are called gametes. When one gamete combines with another gamete, a zygote is formed which has 46 chromosomes.