How does meiosis lead to different gametes and to different offsprings?

Question

i get it for the most part but i'm a little confused anyone wanna drop a few hints?

Answer 1

I had problems understanding this too, but nowadays I know the answer. Only problem is to explain that in English :o)

You have two pairs of chromosomes in each cell. During mitosis, they all split in half (all 2n chromosomes) and grow again, so you get exactly the same cells.

But in meiosis, the pairs are separated (but they are still full, the chromosomes themselves are not halved). 1n goes to one cell and another 1n goes to the other cell. Because each chromosome is different even in the pairs, it means that the offspring cells differ in that each of them has only half of the original chromosomes (randomly chosen).

To get things even more complicated, there is a crossing-over to change even the chromosomes themselves:

"Inside the cells that produce sperm and eggs, chromosomes become paired. While they are pressed together, the chromosomes may break, and each may swap a portion of its genetic material for the matching portion from its mate. This form of recombination is called crossing-over. When the chromosomes glue themselves back together and separate, each has picked up new genetic material from the other. The constellation of physical characteristics it determines is now different than before crossing-over."

I hope it's clear and understandable. If not, check some of these links: