In this review, the use of the most common selection marker genes on plant transformation and the effects of their respective selective agents are discussed. These genes could be divided in two categories according their mode of action: genes for positive and negative selection. The retention of the marker gene flow through chloroplast transformation is also discussed. Further, strategies to re...

Gene targeting is a powerful method for introducing mutations into the genome of embryonic stem cells. The most widely used approach is the positive-negative selection method in which a gene encoding a negative selection marker is cloned into the replacement vector to obtain an enrichment of properly targeted clones. Here, we present an alternative means to introduce any given negative selectio...

We have developed a system for the induction of marker-free mutation of Bacillus subtilis. The system features both the advantages of the use of antibiotic-resistance markers for mutant selection, and the ability to efficiently remove the markers, leaving unmarked mutations in the genome. It utilizes both a selective marker cassette and a counter-selective marker cassette. The selective marker ...

Approximately fifty marker genes used for transgenic and transplastomic plant research or crop development have been assessed for efficiency, biosafety, scientific applications and commercialization. Selectable marker genes can be divided into several categories depending on whether they confer positive or negative selection and whether selection is conditional or non-conditional on the presenc...

MOTIVATION The observation of positive selection acting on a mutant indicates that the corresponding mutation has some form of functional relevance. Determining the fitness effects of mutations thus has relevance to many interesting biological questions. One means of identifying beneficial mutations in an asexual population is to observe changes in the frequency of marked subsets of the populat...