GenHap: a novel computational method based on genetic algorithms for haplotype assembly

Andrea Tangherloni (Corresponding author), Simone Spolaor, Leonardo Rundo, Marco S. Nobile, Paolo Cazzaniga, Giancarlo Mauri, Pietro Liò, Ivan Merelli, Daniela Besozzi

Research output: Contribution to journalArticleAcademicpeer-review

8 Citations (Scopus)
1 Downloads (Pure)

Abstract

Background
In order to fully characterize the genome of an individual, the reconstruction of the two distinct copies of each chromosome, called haplotypes, is essential. The computational problem of inferring the full haplotype of a cell starting from read sequencing data is known as haplotype assembly, and consists in assigning all heterozygous Single Nucleotide Polymorphisms (SNPs) to exactly one of the two chromosomes. Indeed, the knowledge of complete haplotypes is generally more informative than analyzing single SNPs and plays a fundamental role in many medical applications.

Results
To reconstruct the two haplotypes, we addressed the weighted Minimum Error Correction (wMEC) problem, which is a successful approach for haplotype assembly. This NP-hard problem consists in computing the two haplotypes that partition the sequencing reads into two disjoint sub-sets, with the least number of corrections to the SNP values. To this aim, we propose here GenHap, a novel computational method for haplotype assembly based on Genetic Algorithms, yielding optimal solutions by means of a global search process. In order to evaluate the effectiveness of our approach, we run GenHap on two synthetic (yet realistic) datasets, based on the Roche/454 and PacBio RS II sequencing technologies. We compared the performance of GenHap against HapCol, an efficient state-of-the-art algorithm for haplotype phasing. Our results show that GenHap always obtains high accuracy solutions (in terms of haplotype error rate), and is up to 4× faster than HapCol in the case of Roche/454 instances and up to 20× faster when compared on the PacBio RS II dataset. Finally, we assessed the performance of GenHap on two different real datasets.

Conclusions
Future-generation sequencing technologies, producing longer reads with higher coverage, can highly benefit from GenHap, thanks to its capability of efficiently solving large instances of the haplotype assembly problem. Moreover, the optimization approach proposed in GenHap can be extended to the study of allele-specific genomic features, such as expression, methylation and chromatin conformation, by exploiting multi-objective optimization techniques. The source code and the full documentation are available at the following GitHub repository: https://github.com/andrea-tango/GenHap.
Original languageEnglish
Article number172
Number of pages14
JournalBMC Bioinformatics
Volume20
Issue numberSuppl 4
DOIs
Publication statusPublished - 18 Apr 2019
Externally publishedYes

Keywords

  • Combinatorial optimization
  • Future-generation sequencing
  • Genetic algorithms
  • Haplotype assembly
  • Weighted minimum error correction problem
  • Algorithms
  • Time Factors
  • Humans
  • Databases, Genetic
  • Computational Biology/methods
  • Haplotypes/genetics

Fingerprint Dive into the research topics of 'GenHap: a novel computational method based on genetic algorithms for haplotype assembly'. Together they form a unique fingerprint.

Cite this