The finding of disaccord in haplogroup prediction by online software in a father-son pair

The Y-chromosome haplogroup usually determined by the patterns of single nucleotide polymorphism (SNP) refers the geographic or ethnic origin of unknown samples. Recent studies have showed that the haplotypes defined by Y short tandem repeats (STRs) may also be used to predict haplogroup status. The development of online software for Y-haplogroup predictions provides numerous benefits to the forensic application. When samples from a father-son pair in a case were genotyped using the AmpFLSTR® Yfiler® Plus system, mutation at DYS385ab locus (13,14-13,15) was observed. Then haplogroup prediction based on their different haplotypes was conducted with Whit Atheys' haplogroup predictor (http://www.hprg.com/hapest5/hapest5b/hapest5.htm), and disagreement between the father and the son (Q and O3, respectively) was detected. After performing necessary validation using SNP analysis, consistent haplogroup of the father-son pair was assigned. Although Y-STR typing seems more widely used in forensic casework and convenient to predict haplogroup with online tools, our finding suggested that the occurrence of errors in Y-chromosome haplogroup prediction should be cautious. As increasing the number of STRs employed to predict the haplogroup, correcting inaccurate prediction due to mutation is required by means of precise Y-SNP phylogenetic data.