This vignette shows how to process long-read PacBio HiFi variant calls from a validated trio (HG002–HG003–HG004) and prepare them for UPDhmm analysis.

Data source

Ashkenazi trio (GIAB, NIST) – PacBio HiFi Revio, DeepVariant calls (GRCh38).

1. Download phased VCFs for each individual


# Proband (HG002)
wget ftp://ftp-trace.ncbi.nlm.nih.gov/giab/ftp/data/AshkenazimTrio/analysis/PacBio_HiFi-Revio_20231031/pacbio-wgs-wdl_germline_20231031/HG002.GRCh38.deepvariant.phased.vcf.gz
wget ftp://ftp-trace.ncbi.nlm.nih.gov/giab/ftp/data/AshkenazimTrio/analysis/PacBio_HiFi-Revio_20231031/pacbio-wgs-wdl_germline_20231031/HG002.GRCh38.deepvariant.phased.vcf.gz.tbi

# Father (HG003)
wget ftp://ftp-trace.ncbi.nlm.nih.gov/giab/ftp/data/AshkenazimTrio/analysis/PacBio_HiFi-Revio_20231031/pacbio-wgs-wdl_germline_20231031/HG003.GRCh38.deepvariant.phased.vcf.gz
wget ftp://ftp-trace.ncbi.nlm.nih.gov/giab/ftp/data/AshkenazimTrio/analysis/PacBio_HiFi-Revio_20231031/pacbio-wgs-wdl_germline_20231031/HG003.GRCh38.deepvariant.phased.vcf.gz.tbi

# Mother (HG004)
wget ftp://ftp-trace.ncbi.nlm.nih.gov/giab/ftp/data/AshkenazimTrio/analysis/PacBio_HiFi-Revio_20231031/pacbio-wgs-wdl_germline_20231031/HG004.GRCh38.deepvariant.phased.vcf.gz
wget ftp://ftp-trace.ncbi.nlm.nih.gov/giab/ftp/data/AshkenazimTrio/analysis/PacBio_HiFi-Revio_20231031/pacbio-wgs-wdl_germline_20231031/HG004.GRCh38.deepvariant.phased.vcf.gz.tbi

2. Merge individual VCFs into a trio VCF

bcftools merge \
  -O z \
  -o trio_HiFi_GRCh38_phased.vcf.gz \
  HG002.GRCh38.deepvariant.phased.vcf.gz \
  HG003.GRCh38.deepvariant.phased.vcf.gz \
  HG004.GRCh38.deepvariant.phased.vcf.gz

bcftools index trio_HiFi_GRCh38_phased.vcf.gz

3. Filter variants for UPDhmm input

The following filtering steps are applied:

  • keep only biallelic variants

  • remove sites where all trio members are reference (0/0 or 0|0)

  • remove sites where all trio members are missing (./. or .|.)

bcftools view \
  -m2 -M2 \
  -e 'COUNT(GT="0/0" || GT="0|0")==3 || COUNT(GT="./." || GT=".|.")==3' \
  -O z \
  -o trio_HiFi_GRCh38_phased_biallelic_nonref_nomissing.vcf.gz \
  trio_HiFi_GRCh38_phased.vcf.gz

bcftools index trio_HiFi_GRCh38_phased_biallelic_nonref_nomissing.vcf.gz

4. UPDhmm analysis in R

library(UPDhmm)
library(VariantAnnotation)

vcf <- readVcf(
  "trio_HiFi_GRCh38_phased_biallelic_nonref_nomissing.vcf.gz"
)

vcf_check <- vcfCheck(
  <!-- vcf, -->
  proband = "HG002",
  father  = "HG003",
  mother  = "HG004"
)

events <- calculateEvents(
  vcf_check,
  add_ratios = TRUE
)

Session Info

sessionInfo()
## R version 4.6.0 RC (2026-04-17 r89917)
## Platform: x86_64-pc-linux-gnu
## Running under: Ubuntu 24.04.4 LTS
## 
## Matrix products: default
## BLAS:   /home/biocbuild/bbs-3.24-bioc/R/lib/libRblas.so 
## LAPACK: /usr/lib/x86_64-linux-gnu/lapack/liblapack.so.3.12.0  LAPACK version 3.12.0
## 
## locale:
##  [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C              
##  [3] LC_TIME=en_GB              LC_COLLATE=C              
##  [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8   
##  [7] LC_PAPER=en_US.UTF-8       LC_NAME=C                 
##  [9] LC_ADDRESS=C               LC_TELEPHONE=C            
## [11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C       
## 
## time zone: America/New_York
## tzcode source: system (glibc)
## 
## attached base packages:
## [1] stats4    stats     graphics  grDevices utils     datasets  methods  
## [8] base     
## 
## other attached packages:
##  [1] karyoploteR_1.39.0          regioneR_1.45.0            
##  [3] VariantAnnotation_1.59.0    Rsamtools_2.29.0           
##  [5] Biostrings_2.81.2           XVector_0.53.0             
##  [7] SummarizedExperiment_1.43.0 Biobase_2.73.1             
##  [9] GenomicRanges_1.65.0        IRanges_2.47.2             
## [11] S4Vectors_0.51.3            Seqinfo_1.3.0              
## [13] MatrixGenerics_1.25.0       matrixStats_1.5.0          
## [15] BiocGenerics_0.59.6         generics_0.1.4             
## [17] dplyr_1.2.1                 UPDhmm_1.9.0               
## [19] BiocStyle_2.41.0           
## 
## loaded via a namespace (and not attached):
##   [1] DBI_1.3.0                bitops_1.0-9             gridExtra_2.3           
##   [4] rlang_1.2.0              magrittr_2.0.5           biovizBase_1.61.0       
##   [7] otel_0.2.0               compiler_4.6.0           RSQLite_3.53.1          
##  [10] GenomicFeatures_1.65.0   png_0.1-9                vctrs_0.7.3             
##  [13] ProtGenerics_1.45.0      stringr_1.6.0            pkgconfig_2.0.3         
##  [16] crayon_1.5.3             fastmap_1.2.0            magick_2.9.1            
##  [19] backports_1.5.1          rmarkdown_2.31           UCSC.utils_1.9.0        
##  [22] tinytex_0.59             bit_4.6.0                xfun_0.58               
##  [25] cachem_1.1.0             cigarillo_1.3.0          GenomeInfoDb_1.49.1     
##  [28] jsonlite_2.0.0           blob_1.3.0               DelayedArray_0.39.3     
##  [31] BiocParallel_1.47.0      parallel_4.6.0           cluster_2.1.8.2         
##  [34] R6_2.6.1                 stringi_1.8.7            bslib_0.11.0            
##  [37] RColorBrewer_1.1-3       bezier_1.1.2             rtracklayer_1.73.0      
##  [40] rpart_4.1.27             jquerylib_0.1.4          Rcpp_1.1.1-1.1          
##  [43] bookdown_0.46            knitr_1.51               base64enc_0.1-6         
##  [46] BiocBaseUtils_1.15.1     Matrix_1.7-5             nnet_7.3-20             
##  [49] tidyselect_1.2.1         rstudioapi_0.18.0        dichromat_2.0-0.1       
##  [52] abind_1.4-8              yaml_2.3.12              codetools_0.2-20        
##  [55] curl_7.1.0               lattice_0.22-9           tibble_3.3.1            
##  [58] KEGGREST_1.53.0          S7_0.2.2                 evaluate_1.0.5          
##  [61] foreign_0.8-91           pillar_1.11.1            BiocManager_1.30.27     
##  [64] checkmate_2.3.4          RCurl_1.98-1.18          ensembldb_2.37.1        
##  [67] ggplot2_4.0.3            scales_1.4.0             glue_1.8.1              
##  [70] lazyeval_0.2.3           Hmisc_5.2-5              tools_4.6.0             
##  [73] BiocIO_1.23.3            data.table_1.18.4        BSgenome_1.81.0         
##  [76] GenomicAlignments_1.49.0 XML_3.99-0.23            grid_4.6.0              
##  [79] colorspace_2.1-2         AnnotationDbi_1.75.0     htmlTable_2.5.0         
##  [82] restfulr_0.0.16          Formula_1.2-5            cli_3.6.6               
##  [85] HMM_1.0.2                S4Arrays_1.13.0          AnnotationFilter_1.37.0 
##  [88] gtable_0.3.6             sass_0.4.10              digest_0.6.39           
##  [91] SparseArray_1.13.2       rjson_0.2.23             htmlwidgets_1.6.4       
##  [94] farver_2.1.2             memoise_2.0.1            htmltools_0.5.9         
##  [97] lifecycle_1.0.5          httr_1.4.8               bit64_4.8.2             
## [100] bamsignals_1.45.1