01
A gene is a stretch of DNA
A gene contains information that can affect how a cell works. Different versions of a gene are called alleles.
Biology · 24 minutes
Chance deals the alleles
Each parent carries one purple allele, P, and one white allele, p. One allele from each parent enters each seed.
Keep this question in mindHow can information pass from one generation to the next?
01
Notice the problem
A hidden allele can reappear.
Both parents look purple, but each carries a white allele that chance can bring together.
Purple × purpleA hidden allele can reappear.
Both parents look purple, but each carries a white allele that chance can bring together.
02
Three things to notice
Look at these three ideas.
Each picture shows one part of the question. You will test the ideas next.
02
Each parent passes one allele
A pea plant has two alleles for this gene, but each pollen or egg cell receives only one.
03
Dominant does not mean stronger
One P allele is enough for purple flowers in this example. The p allele is still present and can be passed on.
03
Your prediction
What mix should appear across many seeds from Pp × Pp parents?
Choose what you think will happen. It is fine to be wrong. The experiment will help you find out.
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