Final answer:
Mendel's research laid the foundation for understanding inheritance of traits, showing that even though traits can be influenced by multiple genes, the concept of dominant and recessive applies to the traits expressed rather than the genes themselves.
Step-by-step explanation:
Understanding Genetics and Gene Expression
Mendel's work was crucial for the understanding of how traits are passed down from one generation to the next. In his pea plant studies, Mendel established that traits such as color and height were the result of different alleles - variations of a gene. Originally, it was thought that a single gene controls a single trait, but further research has revealed that traits are often the result of multiple genes interacting with one another.
For example, in humans, the trait of eye color is influenced by at least eight genes, illustrating the complexity of gene expression. When discussing dominance in genetics, it's key to note that it is not the gene that is dominant or recessive, but the trait expressed by the allele that is dominant or recessive. This is an important distinction for understanding heritable characteristics.
The concept of epistasis adds another layer to our understanding of genetics, highlighting that gene expression can be influenced by other genes. Mendel's initial idea of a direct one-to-one relationship between gene and trait has evolved to encompass the nuanced interplay between multiple genes and environmental factors in determining an organism's phenotype.