For adults, the most common sources of food allergic reactions are: 1  shellfish (that includes shrimp, lobsters, and crabs) 2  nuts from trees (such as walnuts) 3  fish. 4  eggs. more information...
When binary traits are available, they become classified as Dominant or recessive. A dominant trait is a trait the is evident by the appearance of the organism. A recessive trait is a trait the is present but is not evident in the appearance of the organism. Dark hair is a dominant trait to a recessive light hair trait. Two brunettes may have a chance of having a blonde child due to the fact that either of them may carry the blonde haired gene and not show it.
In genetics, the term dominant gene refers to the allele that causes a phenotype that is seen in a heterozygous genotype. Every person has two copies of every gene, one from mother and one from father. If a genetic trait is dominant, a person only needs to inherit one copy of the gene for the trait to be expressed. Dominance/recessiveness refers to phenotype, not genotype. Consider sickle cell anemia as an example. The sickle cell genotype is caused by a single base pair change in the beta-globin gene.