Recombination in the B chromosome of maize to produce A-B-A chromosomes.
The translocations between the supernumerary B chromosomes and the normal A chromosomes of maize provide a valuable tool for gene localizations, dosage studies and characterization of mutants as null, leaky or gain-of-function. A procedure is described, that relies on recombination in the B chromosome, for marking each of the various B-A translocations with a single dominant marker that will allow dosage classifications of individuals at the mature kernel stage. This marker is R-scm3, which conditions anthocyanin pigment in the aleurone of the endosperm and the scutellum of the embryo. A test for recombination in the B chromosome was conducted by crossing together two translocations, that were broken on opposite sides of the B centromere, and in different A chromosome arms, namely TB-1La and TB-10L18. An example was recovered that linked genetic markers on 1L and 10L to the B centromere. Cytological examination at pachytene of meiosis confirmed the new chromosomal linkage. The use of this procedure to produce a comprehensive set of uniformly marked B-A translocations is discussed.
Birchler
J A
JA
Biological Laboratories, Harvard University, Cambridge, Massachusetts 02138.
Chalfoun
D J
DJ
Levin
D M
DM
D000872:Anthocyanins / Q000235:genetics; D002875:Chromosomes; D008040:Genetic Linkage; D006720:Homozygote; D011995:Recombination, Genetic; D014178:Translocation, Genetic; D003313:Zea mays / Q000235:genetics*
D000872:Anthocyanins