Question

Widows peak is an inherited condition and is a dominant trait. Is it reasonable for a couple to have one child with a widow’s peak and another child without a widow’s peak? Why or why not? Show your work 8. Snapdragons show incomplete dominance. Homozygous dominant snapdragons are red. Heterozygous snapdragons are pink. Homozygous recessive snapdragons are white. Assign letters to each genotype.

Answer 1

Yes, it is reasonable for a couple to have one child with a widow's peak and another without. For snapdragons, homozygous red flowered plants crossed with homozygous white flowered plants produce heterozygous pink-flowered offspring, an example of incomplete dominance.

Step-by-step explanation:

Understanding Inheritance Patterns

It is certainly reasonable for a couple to have one child with a widow's peak and another child without it if one of the parents is heterozygous for the trait (has one dominant and one recessive allele) and the other is homozygous recessive (has two recessive alleles). The dominant allele that causes widow's peak (W) can pair with the recessive allele (w) that does not cause widow's peak. The possible combinations for their children are Ww (with widow's peak) and ww (without widow's peak).

For snapdragons, incomplete dominance is shown when a homozygous red-flowered plant (CRCR) and a homozygous white-flowered plant (CWCW) are crossed, their offspring are heterozygous pink-flowered plants (CRCW). If we assign 'CR' to red and 'CW' to white, the heterozygous plants would then have the genotype 'CRCW' and exhibit pink flowers, representing the intermediate phenotype.

Genotypes and phenotypes of offspring from a self-cross of pink snapdragons (CRCW) can be predicted with a 1:2:1 genotypic ratio and identical phenotypic ratio for red, pink, and white flowers respectively. This demonstrates Mendel's principle of inheritance while illustrating an exception to simple dominance with incomplete dominance.