Predicting Genetic Inheritance Flashcards

All 4 cards in this deck

What are the steps to complete a Punnett square for a monohybrid cross?
e.g. $Dd \times Dd$

1. Write one parent's gametes along the top: $D$ and $d$
2. Write the other parent's gametes down the side: $D$ and $d$
3. Combine the letters in each box: $DD$, $Dd$, $Dd$, $dd$

Two purple-flowered plants produce some white-flowered offspring. What does this tell you about the parents' genotypes?

Both parents are heterozygous ($Pp$) — each carries an allele for white flowers, so some offspring are homozygous recessive ($pp$).

What is a carrier of a genetic disorder?

A heterozygous person who has one recessive allele for the disorder but does not have the disorder, and can pass the allele on.

What ratio of phenotypes is expected from crossing two heterozygous parents (e.g. Dd × Dd)?

3 : 1, dominant to recessive. So there is a 25% (1 in 4) chance of an offspring having the recessive phenotype.