title: HaploPOP: a software that improves population assignment by combining markers into haplotypes.
abstract: BACKGROUND
  In ecology and forensics, some population assignment techniques use molecular markers to assign individuals to known groups. However, assigning individuals to known populations can be difficult if the level of genetic differentiation among populations is small. Most assignment studies handle independent markers, often by pruning markers in Linkage Disequilibrium (LD), ignoring the information contained in the correlation among markers due to LD.
  
  
  RESULTS
  To improve the accuracy of population assignment, we present an algorithm, implemented in the HaploPOP software, that combines markers into haplotypes, without requiring independence. The algorithm is based on the Gain of Informativeness for Assignment that provides a measure to decide if a pair of markers should be combined into haplotypes, or not, in order to improve assignment. Because complete exploration of all possible solutions for constructing haplotypes is computationally prohibitive, our approach uses a greedy algorithm based on windows of fixed sizes. We evaluate the performance of HaploPOP to assign individuals to populations using a split-validation approach. We investigate both simulated SNPs data and dense genotype data from individuals from Spain and Portugal.
  
  
  CONCLUSIONS
  Our results show that constructing haplotypes with HaploPOP can substantially reduce assignment error. The HaploPOP software is freely available as a command-line software at www.ieg.uu.se/Jakobsson/software/HaploPOP/.
authors.affiliation: Univ. Grenoble Alpes, TIMC-IMAG, Grenoble, F-38000, France. duforetn@berkeley.edu.|CNRS, TIMC-IMAG, Grenoble, F-38000, France. duforetn@berkeley.edu.|Department of Integrative Biology, University of California Berkeley, Berkeley, 94720-3140, California, USA. duforetn@berkeley.edu.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Duforet-Frebourg
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden. lucie.gattepaille@gmail.com.
authors.forename: Lucie M
authors.initials: LM
authors.lastname: Gattepaille
authors.affiliation: Univ. Grenoble Alpes, TIMC-IMAG, Grenoble, F-38000, France. michael.blum@imag.fr.|CNRS, TIMC-IMAG, Grenoble, F-38000, France. michael.blum@imag.fr.
authors.forename: Michael G B
authors.initials: MG
authors.lastname: Blum
authors.affiliation: Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden. mattias.jakobsson@ebc.uu.se.|Science for Life Laboratory, Uppsala University, Uppsala, Sweden. mattias.jakobsson@ebc.uu.se.
authors.forename: Mattias
authors.initials: M
authors.lastname: Jakobsson
mesh_terms: D000465:Algorithms; D005828:Genetics, Population; D023281:Genomics; D005838:Genotype; D006239:Haplotypes; D006801:Humans; D020407:Internet; D015810:Linkage Disequilibrium; D020641:Polymorphism, Single Nucleotide; D025341:Principal Component Analysis; D012984:Software