Segregation is one gene. Independent assortment is two.
- The idea
- Predict
- See it
- Why
- Check
The idea
“When a gene's alleles split evenly into gametes, that's independent assortment.”
Both laws come from meiosis and give tidy ratios. So an even split seems to fit either name.
The short version
The mistake: When a gene's alleles split evenly into gametes, that's independent assortment.
What's actually true: Segregation splits one gene's two alleles into different gametes. Independent assortment is two genes sorting independently.
- A diploid cell has two alleles of each gene, one per homologous chromosome. Homologs separate in meiosis I, so each gamete gets one.
- Independent assortment is about genes on different chromosome pairs. Each pair lines up on its own, so A goes with b as often as with B.
- Linked genes, close together on one chromosome, don't assort independently. Each one still segregates.
On the exam: One gene's alleles separating is segregation. Two genes sorting independently is independent assortment.