Correlation of the physical and genetic maps of the centromeric region of the right arm of linkage group III of Neurospora crassa.
We have cloned three linked genes serine-1 (ser-1), proline-1 (pro-1) and acetate-2 (ace-2) that lie near the centromere on the right arm of linkage group III (LGIIIR) of Neurospora crassa. The ser-1 gene was cloned by sib selection. A chromosomal walk that spans 205 kilobases (kb) was initiated from ser-1. Complementation analysis with clones isolated during the walk allowed identification of the pro-1 and ace-2 genes. Restriction fragment length polymorphism analysis has confirmed the localization of ser-1, pro-1 and ace-2 to the centromeric region of LGIIIR. Genetically, we measured 1% recombination between ser-1 and pro-1 and 2% recombination between pro-1 and ace-2. Physical distances for these intervals were 114 kb from ser-1 to pro-1 and 36 kb from pro-1 to ace-2. Thus, for the pro-1 to ace-2 interval we calculate a physical/genetic correlation of 18 kb/map unit (mu) whereas, in the immediately adjacent, centromere-proximal interval from ser-1 to pro-1, we calculate 114 kb/mu. This provides evidence for a centromere effect, a decrease in recombination frequency as one approaches the centromere.
Davis
C R
CR
Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755.
Kempainen
R R
RR
Srodes
M S
MS
McClung
C R
CR
D002503:Centromere; D016386:Chromosome Walking; D015825:Chromosomes, Fungal; D003001:Cloning, Molecular; D008040:Genetic Linkage; D015698:Genomic Library; D009492:Neurospora crassa / Q000235:genetics*; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic; D015183:Restriction Mapping