Domestic plants and animals can be improved or made more useful to humans by the addition of specific genes. Traditionally, genetic improvements have come about by selective cross breeding, a time consuming process. Now, genes can be inserted directly into the DNA, even genes from other species. For example, corn plants have been made resistant to attacks by larvae of the European corn borer by inserting a gene from a bacterium into the corn genome. Genes for human milk proteins can be inserted into cows so that cows will produce human milk. This milk can be used instead of formula by non-breast-feeding babies. Many other applications are under development and the potential is enormous.