In a certain breed of cattle there is incomplete dominance between the allele for red coat and the allele for white coat - Leaving Cert Biology - Question 4 - 2016

Crossing a roan cow with a red bull will result in half of the offspring being roan and half being red. Therefore, there is a 50% chance that a calf from this cross will have a red coat.

When two roan cattle are crossed, the offspring can have three possible coat colors: red, roan, or white, in a ratio of 1:2:1. This results in a 25% chance of a calf having a red coat.

Sex-linkage refers to the inheritance patterns of genes located on the sex chromosomes (X and Y). This often results in traits being inherited differently in males and females, particularly for genes located on the X chromosome.

Human males are more likely to suffer from sex-linked diseases such as haemophilia.

Males have only one X chromosome (XY), so if they inherit the recessive allele for haemophilia from their mother, they will express the disease. On the other hand, females have two X chromosomes (XX). They need to inherit the recessive allele from both parents to express the disease. Therefore, males are more prone to express X-linked recessive disorders than females, who may be carriers.