In shorthorn cattle, coat color may be red, white, or roan. Roan is an intermediate phenotype expressed as a mixture of red and white hairs. The following data were obtained from various crosses: How is coat color inherited? What are the genotypes of parents and offspring for each cross?

Verified step by step guidance

1. <Step 1: Understand the Phenotypes> - In shorthorn cattle, the coat colors are red, white, and roan. Roan is a mixture of red and white hairs, indicating incomplete dominance between the red and white alleles.
2. <Step 2: Define the Alleles> - Assign alleles to the coat colors: let 'R' represent the red allele and 'W' represent the white allele. Roan, being a mixture, would be represented by the heterozygous genotype 'RW'.
3. <Step 3: Analyze the Crosses> - For each cross, determine the possible genotypes of the parents based on the phenotypes of the offspring. Use a Punnett square to predict the genotypic and phenotypic ratios of the offspring.
4. <Step 4: Determine Genotypes of Parents> - If a cross between two roan cattle (RW x RW) results in red, white, and roan offspring, this supports the incomplete dominance model. Analyze other crosses similarly to deduce parental genotypes.
5. <Step 5: Summarize Inheritance Pattern> - Conclude that coat color in shorthorn cattle is inherited through incomplete dominance, where the heterozygous genotype results in the roan phenotype. Confirm this pattern with the data from the crosses.

Key Concepts

Inheritance Patterns

Coat color in shorthorn cattle demonstrates a classic example of incomplete dominance, where neither allele is completely dominant over the other. In this case, the red and white alleles produce a roan phenotype when combined, resulting in a blend of traits. Understanding this pattern is crucial for predicting the genotypes and phenotypes of offspring based on parental combinations.

Genotype and Phenotype

The genotype refers to the genetic makeup of an organism, while the phenotype is the observable expression of that genotype. In shorthorn cattle, the genotypes can be represented as RR (red), WW (white), and RW (roan). Recognizing the relationship between genotype and phenotype is essential for determining the expected outcomes of genetic crosses.

Punnett Squares

Punnett squares are a tool used to predict the genotypic and phenotypic ratios of offspring from genetic crosses. By organizing the possible gametes from each parent, a Punnett square allows for a visual representation of inheritance patterns. This method is particularly useful in understanding the inheritance of coat color in shorthorn cattle and calculating the likelihood of different phenotypes in the offspring.