Original: He is known chiefly for suggesting the concept of genes, rediscovering the laws of heredity in the 1890s while unaware of Gregor Mendel's work, for introducing the term "mutation", and for developing a mutation theory of evolution.
Simplified: He is known chiefly for suggesting the concept of genes, rediscovering Gregor Mendel's laws of heredity in the 1890s, and for developing a mutation theory of evolution.