Construction of a 10,000-marker ultradense genetic recombination map of potato: providing a framework for accelerated gene isolation and a genomewide physical map.
An ultradense genetic linkage map with >10,000 AFLP loci was constructed from a heterozygous diploid potato population. To our knowledge, this is the densest meiotic recombination map ever constructed. A fast marker-ordering algorithm was used, based on the minimization of the total number of recombination events within a given marker order in combination with genotyping error-detection software. This resulted in "skeleton bin maps," which can be viewed as the most parsimonious marker order. The unit of distance is not expressed in centimorgans but in "bins." A bin is a position on the genetic map with a unique segregation pattern that is separated from adjacent bins by a single recombination event. Putative centromeres were identified by a strong clustering of markers, probably due to cold spots for recombination. Conversely, recombination hot spots resulted in large intervals of up to 15 cM without markers. The current level of marker saturation suggests that marker density is proportional to physical distance and independent of recombination frequency. Most chromatids (92%) recombined once or never, suggesting strong chiasma interference. Absolute chiasma interference within a chromosome arm could not be demonstrated. Two examples of contig construction and map-based cloning have demonstrated that the marker spacing was in accordance with the expected physical distance: approximately one marker per BAC length. Currently, the markers are used for genetic anchoring of a physical map of potato to deliver a sequence-ready minimal tiling path of BAC contigs of specific chromosomal regions for the potato genome sequencing consortium (http://www.potatogenome.net).
Laboratory of Plant Breeding, Wageningen University, The Netherlands.
Hans
H
van Os
Sandra
S
Andrzejewski
Erin
E
Bakker
Imanol
I
Barrena
Glenn J
GJ
Bryan
Bernard
B
Caromel
Bilal
B
Ghareeb
Edwige
E
Isidore
Walter
W
de Jong
Paul
P
van Koert
Véronique
V
Lefebvre
Dan
D
Milbourne
Enrique
E
Ritter
Jeroen N A M Rouppe
JN
van der Voort
Françoise
F
Rousselle-Bourgeois
Joke
J
van Vliet
Robbie
R
Waugh
Richard G F
RG
Visser
Jaap
J
Bakker
Herman J
HJ
van Eck
D002874:Chromosome Mapping; D004171:Diploidy; D005819:Genetic Markers; D018745:Genome, Plant; D006579:Heterozygote; D008540:Meiosis / Q000235:genetics; D040641:Quantitative Trait Loci; D011995:Recombination, Genetic; D015183:Restriction Mapping; D011198:Solanum tuberosum / Q000235:genetics*
D005819:Genetic Markers