title: Development and characterization of BAC-end sequence derived SSRs, and their incorporation into a new higher density genetic map for cultivated peanut (Arachis hypogaea L.).
abstract: BACKGROUND
  Cultivated peanut (Arachis hypogaea L.) is an important crop worldwide, valued for its edible oil and digestible protein. It has a very narrow genetic base that may well derive from a relatively recent single polyploidization event. Accordingly molecular markers have low levels of polymorphism and the number of polymorphic molecular markers available for cultivated peanut is still limiting.
  
  
  RESULTS
  Here, we report a large set of BAC-end sequences (BES), use them for developing SSR (BES-SSR) markers, and apply them in genetic linkage mapping. The majority of BESs had no detectable homology to known genes (49.5%) followed by sequences with similarity to known genes (44.3%), and miscellaneous sequences (6.2%) such as transposable element, retroelement, and organelle sequences. A total of 1,424 SSRs were identified from 36,435 BESs. Among these identified SSRs, dinucleotide (47.4%) and trinucleotide (37.1%) SSRs were predominant. The new set of 1,152 SSRs as well as about 4,000 published or unpublished SSRs were screened against two parents of a mapping population, generating 385 polymorphic loci. A genetic linkage map was constructed, consisting of 318 loci onto 21 linkage groups and covering a total of 1,674.4 cM, with an average distance of 5.3 cM between adjacent loci. Two markers related to resistance gene homologs (RGH) were mapped to two different groups, thus anchoring 1 RGH-BAC contig and 1 singleton.
  
  
  CONCLUSIONS
  The SSRs mined from BESs will be of use in further molecular analysis of the peanut genome, providing a novel set of markers, genetically anchoring BAC clones, and incorporating gene sequences into a linkage map. This will aid in the identification of markers linked to genes of interest and map-based cloning.
authors.affiliation: Tuskegee University, Tuskegee, AL 36088, USA.
authors.forename: Hui
authors.initials: H
authors.lastname: Wang
authors.forename: R Varma
authors.initials: RV
authors.lastname: Penmetsa
authors.forename: Mei
authors.initials: M
authors.lastname: Yuan
authors.forename: Limin
authors.initials: L
authors.lastname: Gong
authors.forename: Yongli
authors.initials: Y
authors.lastname: Zhao
authors.forename: Baozhu
authors.initials: B
authors.lastname: Guo
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Farmer
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Rosen
authors.forename: Jinliang
authors.initials: J
authors.lastname: Gao
authors.forename: Sachiko
authors.initials: S
authors.lastname: Isobe
authors.forename: David J
authors.initials: DJ
authors.lastname: Bertioli
authors.forename: Rajeev K
authors.initials: RK
authors.lastname: Varshney
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Cook
authors.forename: Guohao
authors.initials: G
authors.lastname: He
mesh_terms: D010367:Arachis / Q000235:genetics*; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D008040:Genetic Linkage; D005819:Genetic Markers; D018745:Genome, Plant; D017422:Sequence Analysis, DNA; D018911:Trinucleotide Repeats
chemical_list: D018744:DNA, Plant; D005819:Genetic Markers