hrefinder

This software detects homologous recombination events (HREs) from SNP data. Based on SNP alleles calls and locations, it breaks the genomes into locally colinear blocks, and looks for cases where SNPs do not agree with the vertical pattern of inheritance in a phylogeny. It applies a dynamic programming algorithm to model whether changes within a block are likely a result of mutations, sequencing errors, or HRE. We use information from the nearby SNPs, so that if 1-2 alleles in a series of SNPs differs from the ancestral allele, it may be better explained as a mutation or sequencing error. But if a series of SNP alleles differ from the ancestral pattern, then it may be more likely that an HRE has occurred, particularly if the allele pattern matches that from another part of the tree better than that of the ancestral node.