 In addition to simply maintaining an isolated recessive lethal (or sterile) mutation, balancer chromosomes are also used in forward genetic screens to identify such mutations.
<clarity>  In addition to simply maintaining an isolated recessive lethal (or sterile) mutation, balancer chromosomes are also used in forward genetic screens to identify such mutations.
 In addition to simply maintaining an isolated recessive lethal (or sterile) mutation, balancer chromosomes are also useful in forward genetic screens to identify such mutations.