Question

J indicates the allele for jagged-edged leaves j indicates the allele for smooth-edged leaves. Which statement about the offspring is correct if a cross between JJ and Jj was conducted

Answer 1

In a cross between a JJ plant and a Jj plant, all the offspring will have jagged-edged leaves as J is the dominant allele for leaf edge. The offspring may be either homozygous dominant (JJ) or heterozygous (Jj), but will phenotypically show the dominant trait.

Step-by-step explanation:

If a cross is conducted between a plant with jagged-edged leaves (JJ) and a plant with one jagged-edged leaf allele and one smooth-edged leaf allele (Jj), we can predict the possible genotypes of the offspring. This can be represented by a simple Punnett square, which is a chart that allows us to easily determine the genetic combinations that can result from a cross.

Since JJ is homozygous dominant and Jj is heterozygous, the alleles from the JJ parent can only contribute 'J' to the offspring, while the alleles from the Jj parent can contribute either 'J' or 'j' to the offspring. This results in the following possible combinations:

• Offspring 1: J (from JJ parent) + J (from Jj parent) = JJ (jagged-edged leaves)
• Offspring 2: J (from JJ parent) + j (from Jj parent) = Jj (jagged-edged leaves)

Therefore, the correct statement about the offspring is that all of them will have jagged-edged leaves because 'J' is the dominant trait. The offspring will be genotypically either homozygous dominant (JJ) or heterozygous (Jj), but both of these genotypes result in the dominant jagged-edged leaf phenotype.