Chromosome Landing Using an AFLPTWased Strategy

Chromosome walking and, more recently, chromosome landing experiments have been successfully used in higher plants to identify genes correlated with specific genetic 1oc1 (1 ,2 ; for a review, see ref. 3 ). In Arabidopsis thaliana, these strategies are mainly used for mapping recessive mutations (see Note 1 ) as are described here. Both approaches require a rough map position of the target locus to start with To thts end, the mutant IS crossed with a wild-type plant of another genetic background. The resultant F1 plants are self-fertlhzed and the F2 progeny 1s used to determine the initial map positlon relative to molecular markers. DNA markers such as cleaved amplified polymorphic sequences (CAPS), simple sequence repeats (SSRs), and Arabidopsis restriction fragment length polymorphism (RFLP) mapping sets (ARMS) were identified between the Arabidopszs ecotypes Columbia and Landsberg erecta but can also be used in other ecotypes (see refs. 4 -6 and Chapters 21 and 22 ). These codominant markers allow rapid and efficient rough mapping.