A homozygous short dog (dd) is crossed with a heterozygous tall dog (Dd). What is the probability that the offspring will be short?

Not sure ?

50%

dd x Dd= Dd Dd dd dd

Thanks so much! Still learning how to do this.

keep using punnet squares to cross the genotypes of parents!

50%

To determine the probability of the offspring being short, we need to understand how traits are inherited in this scenario. In this case, the gene for height has two versions or alleles: "D" for tall and "d" for short.

Let's break down the cross between a homozygous short dog (dd) and a heterozygous tall dog (Dd):

The homozygous short dog has both alleles as "d" (dd). This means that it can only pass on the "d" allele to its offspring.

The heterozygous tall dog has one allele for tall (D) and one allele for short (d) (Dd). This dog can pass either a "D" or a "d" allele to its offspring.

Using a Punnett square, we can determine the possible combinations of alleles in the offspring:

| D d
---|---|---
d | Dd dd

There are two possible genotypes for the offspring: Dd and dd. Out of these, only the genotype dd represents a short dog.

Therefore, the probability of the offspring being short (dd) is 1 out of 2, or 1/2.

To summarize, the probability of the offspring being short when crossing a homozygous short dog (dd) with a heterozygous tall dog (Dd) is 1/2.