Final answer:
Genomic imprinting is the term for when genes vary in their phenotypic expression based on the sex of the parent it was inherited from. Phenotypic traits are influenced by both the organism's genotype and environmental factors, illustrating complexity beyond Mendelian genetics such as X-linked gene expression.
Step-by-step explanation:
The phenomenon where genes and mutations vary in their phenotypic expression depending on the sex of the parent from whom the gene is inherited is known as genomic imprinting.
An organism's phenotype is the observable traits expressed by the organism, which are influenced by the genotype or the underlying genetic makeup with both visible and non-expressed alleles. Genes that are inherited from one parent can sometimes be expressed in a way that is dependent on which parent contributed them. For instance, X-linked genes present on the X chromosome can result in different phenotypic expressions in males and females since males only have one X chromosome.
Mendelian genetics explains the relationship between genotype and phenotype, such as in Mendel's hybridization experiments with peas. However, not all genetic expression follows strict dominant and recessive patterns, such as the case with incomplete dominance, codominance, or X-linked genes. Additionally, similar to how the expression of certain traits can be influenced by genomic imprinting, environmental factors can also prompt different gene expression which leads to variability among individuals despite having the same genotype.