Identical genes mean shared weaknesses
- The idea
- Predict
- See it
- Why
- Check
The idea
“A population of genetically identical individuals is stronger, since they're all equally healthy.”
A field of identical plants sounds like quality control. If one is healthy, they all are, and that logic runs just as well the other way.
The short version
The mistake: A population of genetically identical individuals is stronger, since they're all equally healthy.
What's actually true: Identical individuals share every weakness, so one new threat can hit them all. Variation makes it likely that some survive.
- Clones carry the same alleles. A weakness one has, they all have, so one disease or one hot summer can hit every individual at once.
- In a varied population, individuals carry different alleles. When conditions change, some are likely to survive and reproduce. Natural selection acts on that variation.
- A clone can get lucky and resist one disease. Every new pathogen or climate shift then tests that same single genotype again.
On the exam: Identical individuals all meet a new threat the same way. Variation gives some a chance to survive.