Pedigree Based Analysis using FlexQTL TM software Marco Bink Eric van de Weg Roeland Voorrips Hans Jansen
Outline Current Status: QTL mapping in pedigreed populations IBD probability of founder alleles Marker consistency checking Targets for RosBREED project Questions & discussion
FlexQTL software - 2 modules +. Quantitative trait analysis (QTL mapping) Pedigree, trait phenotypes, markers genotypes, linkage map Dissection of quantitative traits into non-genetic and genetic components Identity By Descent (IBD) probability Pedigree, marker genotypes, linkage map Founder alleles Visualization via Pedimap software Regression analyses, e.g., fitting multiple alleles or interactions Founder allele representation Marker data checking Pedigree, marker genotypes, linkage map Consistency & informativeness
Example on segregation errors aap 4 4 noot 5 1 aap 4 4 noot 5 1 mies 2 1 jet 14 31 Allele 3 erroroneous mies 2 1 jet 4 1 Genotype corrected teun 2 4 vuur 2 1 teun 2 4 vuur 2 1
Example - Reporting marker consistency LocusName marker001 (1) 1 2 3 4 5 ;alleles coded in FlexQTL 1 2 3 4 5 ;alleles original in data jet marker001 1,3 1,3 1 3 0.0000 (<-) 4 1 0.9999 Putative deletion: -log(p) jet marker001 99.31 Realised deletion: jet marker001 99.31 1 3 Augmentation step: jet marker001 1,3 4,1 4 1 0.9999 (<-) Detected segregation errors: 0 Augmented marker genotypes : 1
MARKER GENOTYPE ERRORS ************************************************************ Indicator : FlexQTL-code : Explanation. : 0 : (OC) observed & consistent ^ : 2 : (OpE) observed & putative error! : 1 : (OdE) observed & deleted error # : 5 : (OdEA)observed & deleted error & augmented / : 8 : (ME) missing & error + : 4 : (MA) missing & augmented _ : 9 : (M) missing : : next linkage group ************************************************************ MARKER GENOTYPE PATTERN... ; aap... ; noot... ; mies... ; wim... ; zus... ; jet MARKER GENOTYPE PATTERN... ; aap..._. ; noot...+. ; mies...+. ; wim...+. ; zus #.##+# ; jet
Marker information: segregation indicators Parent 1 Parent 2 A B C C Parent 1 Parent 2 A B C C A C 0 - Individual X Individual X Used symbols & their explanation: _ not available or not informative (parent homozygous genotype) 0 paternal allele of its parent 1 maternal allele of its parent s undetermined, i.e., similar heterozygous genotypes indiv & parent(s)
Marker information: segregation indicators Parent 1 Parent 2 A B C C - - B C A C A C B B C A A C B C A C B C Individual X 0 - - s s s - 0 Individual X 4 polymorphic markers: limited information on segregation Used symbols & their explanation: _ not available or not informative (parent homozygous genotype) 0 paternal allele of its parent 1 maternal allele of its parent s undetermined, i.e., similar heterozygous genotypes indiv & parent(s)
Segregation indicators (SI): Used symbols & their explanation: _ not available or not informative (parent homozygous genotype) 0 paternal allele of its parent 1 maternal allele of its parent s undetermined, i.e., similar heterozygous genotypes indiv & parent(s) haplotype SI values progeny Marker loci 1 2 3 4 5 6 parent 4 4 5 5 1 5 4 5 1 4 1 1 400 _ 1 1 1 _ 1 401 _ 1 0 1 _ 1 402 _ 0 0 0 _ 1 Double 403 _ 0 s 0 _ 0 recombinant 404 _ 1 1 1 _ 1 405 _ 1 s 0 _ 0
Marker consistency checking Consecutive triplets of informative meisoses Two meiosis events per non-founder individual Observed number of Double Recombinants Based on observed dataset Expected number of Double Recombinants Based on informative meiosis events Based on given marker map distances
Map order & Double Recombinants: Example Correct order Informative M 0.2 0.0 0 20 40 60 80 100 1 marker001 marker002 marker003 marker004 marker005 marker006 Erroneous order Switched markers 2 & 3 Informative M 0.2 0.0 0 20 40 60 80 100 1 marker001 marker003 marker002 marker004 marker005 marker006
FlexQTL TM targets: where to go? Training course materials (June 15-16, Michigan State Univ, E. Lansing, MI) User friendliness of FlexQTL: Improve current functionalities Graphical User-Interface, e.g., window-based input User-friendly output (easier to interpret) Add new functionalities Infer linkage phase of marker and QTL alleles. Ability to deal with semi-founders Founder (allele) representation Data exchange Add-on tools (decision support) & Database Scientific extensions: Polyploids (conceptually challenging; extension programming) Marker density: High density maps & founder alleles relatedness QTL modeling: multi-allelic & interactions (env ment & epistasis)
Acknowledgements This project was supported by the Specialty Crops Research Initiative of USDA s National Institute of Food and Agriculture