README.md

Scripts for the Publication:

Introgression patterns between house mouse subspecies and species reveal genomic windows of frequent exchange

Ullrich KK, Linnenbrink M, McConnell E, Tautz D

Data sources

Genomic sequence data files for Mus musculus domesticus GER, Mus musculus domesticus FRA, Mus musculus domesticus IRA, Mus musculus musculus AFG, Mus musculus castaneus CAS and Mus spretus SPRE were obtained from the European Nucleotide Archive https://www.ebi.ac.uk/ena according to table 1 from the original publication (Harr et al. 2016) https://www.nature.com/articles/sdata201675/tables/1 (see also https://www.ebi.ac.uk/ena/data/view/PRJEB9450, https://www.ebi.ac.uk/ena/data/view/PRJEB11742, https://www.ebi.ac.uk/ena/data/view/PRJEB14167, https://www.ebi.ac.uk/ena/data/view/PRJEB2176).

Mapping

Genome sequencing reads were mapped against mm10 version of the mouse reference genome (GRCm38/mm10) with 'ngm' (Sedlazeck et al. 2013), followed by sorting, marking and removing duplicates with the picard software suite (https://broadinstitute.github.io/picard/).

#example for one Mus musculus musculus individual - AFG1 - 396
wget ftp://ftp.sra.ebi.ac.uk/vol1/fastq/ERR142/005/ERR1425295/ERR1425295_1.fastq.gz
wget ftp://ftp.sra.ebi.ac.uk/vol1/fastq/ERR142/006/ERR1425296/ERR1425296_1.fastq.gz
wget ftp://ftp.sra.ebi.ac.uk/vol1/fastq/ERR142/007/ERR1425297/ERR1425297_1.fastq.gz
wget ftp://ftp.sra.ebi.ac.uk/vol1/fastq/ERR142/008/ERR1425298/ERR1425298_1.fastq.gz

zcat ERR1425295_1.fastq.gz >> Mmm_AFG.396.1.fq
zcat ERR1425296_1.fastq.gz >> Mmm_AFG.396.1.fq
zcat ERR1425297_1.fastq.gz >> Mmm_AFG.396.1.fq
zcat ERR1425298_1.fastq.gz >> Mmm_AFG.396.1.fq

wget ftp://ftp.sra.ebi.ac.uk/vol1/fastq/ERR142/005/ERR1425295/ERR1425295_2.fastq.gz
wget ftp://ftp.sra.ebi.ac.uk/vol1/fastq/ERR142/006/ERR1425296/ERR1425296_2.fastq.gz
wget ftp://ftp.sra.ebi.ac.uk/vol1/fastq/ERR142/007/ERR1425297/ERR1425297_2.fastq.gz
wget ftp://ftp.sra.ebi.ac.uk/vol1/fastq/ERR142/008/ERR1425298/ERR1425298_2.fastq.gz

zcat ERR1425295_2.fastq.gz >> Mmm_AFG.396.2.fq
zcat ERR1425296_2.fastq.gz >> Mmm_AFG.396.2.fq
zcat ERR1425297_2.fastq.gz >> Mmm_AFG.396.2.fq
zcat ERR1425298_2.fastq.gz >> Mmm_AFG.396.2.fq

FWD=Mmm_AFG.396.1.fq
REV=Mmm_AFG.396.2.fq
NGMOUTPUT=Mmm_AFG.396.mm10.sam
RGID=396
RGSM=396

ngm -1 $FWD -2 $REV -r mm10.fasta -o $NGMOUTPUT --no-unal --sensitive -t 24 --no-progress --rg-id $RGID --rg-sm $RGSM --rg-lb lib1 --rg-pl illumina --rg-pu unit1 -b

NGMSORTEDOUTPUT=Mmm_AFG.396.mm10.sorted.bam

java -jar picard.jar SortSam I=$NGMOUTPUT O=$NGMSORTEDOUTPUT SO=coordinate

NODUPOUTPUT=Mmm_AFG.396.mm10.sorted.nodup.bam
DUPMETRICS=Mmm_AFG.396.mm10.sorted.duplicate.metrics

java -jar picard.jar MarkDuplicates I=$NGMSORTEDOUTPUT O=$NODUPOUTPUT M=$DUPMETRICS REMOVE_DUPLICATES=true

used software:

• NextGenMap 0.5.3
• picard.jar 2.9.2-SNAPSHOT

Construction of consensus sequences for natural populations

To construct population specific consensus sequences, we used ANGSD and the 'doFasta 2' option.

CONSENSUS FASTA

In addition to the 'doFasta 2' optin, which extracts the most common nucleotide, other filters like 'minQ' and coverage filters like 'setMinDepthInd' and 'setMaxDepthInd' were applied.

CONSENSUS FASTA example for the population Mus musculus musculus AFG:

#example for populaton Mmm_AFG for chr1

#used BAM files:

#Mmm_AFG.396.mm10.sorted.nodup.bam
#Mmm_AFG.413.mm10.sorted.nodup.bam
#Mmm_AFG.416.mm10.sorted.nodup.bam
#Mmm_AFG.424.mm10.sorted.nodup.bam
#Mmm_AFG.435.mm10.sorted.nodup.bam
#Mmm_AFG.444.mm10.sorted.nodup.bam

echo Mmm_AFG.396.mm10.sorted.nodup.bam >> AFG.list
echo Mmm_AFG.413.mm10.sorted.nodup.bam >> AFG.list
echo Mmm_AFG.416.mm10.sorted.nodup.bam >> AFG.list
echo Mmm_AFG.424.mm10.sorted.nodup.bam >> AFG.list
echo Mmm_AFG.435.mm10.sorted.nodup.bam >> AFG.list
echo Mmm_AFG.444.mm10.sorted.nodup.bam >> AFG.list

angsd -doFasta 2 -doCounts 1 -minQ 13 -uniqueOnly -setMinDepthInd 5 -setMaxDepthInd 100 -b AFG.list -r chr1 -out AFG.ngm.minQ13.uniqueOnly.setMinDepthInd5.setMaxDepthInd100.chr1

used software:

• ANGSD v0.919 http://www.popgen.dk/angsd/index.php/ANGSD

NOTE: Population consensus sequences were merged for each chromosome.

All CONSENSUS FASTA files can be obtained from:

http://wwwuser.gwdg.de/~evolbio/evolgen/wildmouse/introgression/ngm/fasta/pop/

Construction of individual sequences using IUPAC code

To construct individual sequences, we used ANGSD and the 'doFasta 4' option. For this option, after all filters have been applied, all multi-allelic sites will be encoded as IUPAC code.

INDIVIDUAL FASTA

In addition to the 'doFasta 4' optin, which extracts IUPAC code, other filters like 'minQ' and coverage filters like 'setMinDepthInd' and 'setMaxDepthInd' were applied.

CONSENSUS FASTA example for the population Mus musculus musculus AFG:

#example for one Mus musculus musculus individual - AFG1 - 396 for chr1

#used BAM file:

#Mmm_AFG.396.mm10.sorted.nodup.bam

angsd -doFasta 4 -doCounts 1 -minQ 13 -uniqueOnly -setMinDepthInd 5 -setMaxDepthInd 100 -i Mmm_AFG.396.mm10.sorted.nodup.bam -r chr1 -out AFG.396.ngm.minQ13.uniqueOnly.setMinDepthInd5.setMaxDepthInd100.chr1

used software:

• ANGSD v0.919 http://www.popgen.dk/angsd/index.php/ANGSD

NOTE: Individual sequences were merged for each chromosome.

All INDIVIDUAL FASTA files can be obtained from:

http://wwwuser.gwdg.de/~evolbio/evolgen/wildmouse/introgression/ngm/fasta/ind/

K80 distance calculation

Calculate dK80 distance between populations using the CONSENSUS pseudo-genome files

To calculate dK80 distance between populations, quartets ([X],[Y],[Z],[O]) are used. Within the population quartets, dK80 is calculated for trios (e.g. [X],[Z],[O]) on non-verlapping sequence windows (w) throughout the investigated genome between this population triplet on a window (w_{i}) as: \begin{equation} dK80_{XZO_{w_{i}}} = d_{XO_{w_{i}}} - d_{XZ_{w_{i}}} \end{equation} where $d_{XO_{w_{i}}} and d_{XZ_{w_{i}}} are defined as the average Kimura's 2-parameter sequence distance (Kimura 1980) between the corresponding two populations calculated with the function 'dist.dna' of the of the R package 'ape' (Paradis et al. 2004) using the model 'K80'. Prior the calculation of dK80 all sites with missing data within the specified window (w_{i}$) and the specified populations were removed across the whole quartet with the 'Biostrings' R package (Pages et al. 2009).

example for chromosome 1 for the dK80 calculation for the quartet [X]: _Mus musculus domesticus FRA; [Y]: _Mus musculus domesticus GER; [Z]: _Mus musculus domesticus IRA; [O]: Mus musculus musculus AFG:

#example for the quartet [X]: FRA; [Y]: GER; [Z]: IRA; [O]: AFG

#change the bottom part of the script 'get_dK80.r' for each chromosome and quartet

#here you can find the example for chromosome 1

popX <- "Mmd_FRA"
popY <- "Mmd_GER"
popZ <- "Mmd_IRA"
popO <- "Mmm_AFG"

TMP_DIR <- "/tmp"

popX.pos <- 2
popY.pos <- 3
popZ.pos <- 4
popO.pos <- 1

SEQ_FILE <- "http://wwwuser.gwdg.de/~evolbio/evolgen/wildmouse/introgression/ngm/fasta/pop/chr1.ngm.minQ13.uniqueOnly.setMinDepthInd5.setMaxDepthInd100.fa"
chr <- "chr1"
OUT_FILE <- paste0(TMP_DIR,"/",popX,"_",popY,".",popZ,".",popO,".",chr,".tsv")

WSIZE <- 25000
WJUMP <- 25000

DISTMODEL <- "K80"

#to run the script
nohup nice R CMD BATCH --vanilla get_dK80.r &

#result file will be in this case:

tail -f /tmp/Mmd_FRA_Mmd_GER.Mmd_IRA.Mmm_AFG.chr1.tsv

All dK80 files can be obtained from:

http://wwwuser.gwdg.de/~evolbio/evolgen/wildmouse/introgression/ngm/dK80/

NOTE: For each quartet comparison all analyzed chromosomes were merged into one file.