Two Shuffles, Eight Million Hands

You'll learnhow crossing over, independent assortment, and random fertilization each add genetic variation.

One small cell runs meiosis and four different gametes come out. Two shuffles inside meiosis — crossing over in prophase I, independent assortment at metaphase I — and one random draw after it are why no two ever match. Twelve short steps; press Next for each one.

AP BIOLOGY · 12 STEPS · 6 QUICK CHECKS · CROSSING OVER = PROPHASE I · ASSORTMENT = METAPHASE I · v6

two pairs in · four different gametes out · shuffled, never copied

Before you start

What you're looking at

A small parent cell with two homolog pairs, a maternal and a paternal homologue in each, carrying labeled gene loci.

The question

Why are the four gametes from one meiosis different cells rather than four copies?

Step 1 / 12