ipyrad command line tutorial - Part II
This is the second part of the full tutorial for the command line interface for ipyrad. In the previous section we imported our data, did some QC, and created clusters of similar reads within each sample. In this section, we continue with the assembly, with the goal of calling bases, clustering across samples based on consensus sequence similarity, and then finally writing output in various useful formats.
Each grey cell in this tutorial indicates a command line interaction.
Lines starting with $ indicate a command that should be executed
in a terminal connected to the USP cluster, for example by copying and
pasting the text into your terminal. All lines in code cells beginning
with ## are comments and should not be copied and executed. Elements
in code cells surrounded by angle brackets (e.g.
## Example Code Cell.
## Create an empty file in my home directory called `watdo.txt`
$ touch ~/watdo.txt
## Print "wat" to the screen
$ echo "wat"
wat
Getting set up to continue the assembly
As a reminder, we are running assembly of the simulated data inside binder instances running on “the cloud”. A small headache is that if you let your binder sit long enough it’ll time out and die, in which case you’ll have to redo all the setup, config, and assembly up to the point where you paused. If your binder dies for whatever reason you can grab and run the binder-reinstall.sh and it’ll bring you right back up to speed!
- Open a new binder instance
- Get a New>Terminal and execute these commands (takes ~5 minutes):
$ wget https://radcamp.github.io/Marseille2020/binder-reinstall.sh
$ bash binder-reinstall.sh
Step 3: Recap
Recall that we clustered reads within samples in Step 3. Reads that are sufficiently
similar (based on the specified sequence similarity threshold) are grouped together
in clusters separated by “//”. We examined the head of one of the sample cluster
files at the end of the last exercise, but here we’ve cherry picked a couple
clusters with more pronounced features.
Here’s a nice homozygous cluster, with probably one read with sequencing error:
0082e23d9badff5470eeb45ac0fdd2bd;size=5;*
TGCATGTAGTGAAGTCCGCTGTGTACTTGCGAGAGAATGAGTAGTCCTTCATGCA
a2c441646bb25089cd933119f13fb687;size=1;+
TGCATGTAGTGAAGTCCGCTGTGTACTTGCGAGAGAATGAGCAGTCCTTCATGCA
Here’s a probable heterozygote, or perhaps repetitive element – a little bit messier (note the indels):
0091f3b72bfc97c4705b4485c2208bdb;size=3;*
TGCATACAC----GCACACA----GTAGTAGTACTACTTTTTGTTAACTGCAGCATGCA
9c57902b4d8e22d0cda3b93f1b361e78;size=3;-
TGCATACAC----ACACACAACCAGTAGTAGTATTACTTTTTGTTAACTGCAGCATGCA
d48b3c7b5a0f1840f54f6c7808ca726e;size=1;+
TGCATACAC----ACAAACAACCAGTTGTAGTACTACTTTTTGTTAACTGCAGCATGAA
fac0c64aeb8afaa5dfecd5254b81b3c0;size=1;+
TGCATACAC----GCACACAACCAGTAGTAGTACTACTTTTTGTTAACTGCAGCATGTA
f31cbca6df64e7b9cb4142f57e607a88;size=1;-
TGCATGCACACACGCACGCAACCAGTAGTTGTACTACTTTTTGTTAACTGCAGCATGCA
935063406d92c8c995d313b3b22c6484;size=1;-
TGCATGCATACACGCCCACAACCAGTAGTAGTACAACTTTATGTTAACTGCAGCATGCA
d25fcc78f14544bcb42629ed2403ce74;size=1;+
TGCATACAC----GCACACAACCAGTAGTAGTACTACTTTTTGTTAATTGCAGCATGCA
Here’s a nasty one!
008a116c7a22d6af3541f87b36a8d895;size=3;*
TGCATTCCTATGGGAATCATGAAGGGGCTTCTCTCTCCCTCA-TTTTTAAAGCGACCCTTTCCAAACTTGGTACAT----
a7bde31f2034d2e544400c62b1d3cbd5;size=2;+
TGCATTCCTATGGGAAACATGAAGGGACTTCTCTCTCCCTCG-TTTTTAAAGTGACTCTGTCCAAACTTGGTACAT----
107e1390e1ac8564619a278fdae3f009;size=2;+
TGCATTCCTATGGGAAACATGAAGGGGGTTCTCTCTCCCTCG-ATTTTAAAGCGACCCTGTCCAAACTTGGTACAT----
8f870175fb30eed3027b7aec436e93e6;size=2;+
TGCATTCCTATGGGAATCATGGAAGGGCTTCTCTCTCCCTCA-TTTTTAAAGCAACCCTGACCAAAGTTGGTACAT----
445157bc1e7540734bf963eb8629d827;size=2;+
TGCATTCCTACGGGAATCATGGAGGGGCTTCTCTCTCCCTCG-TTTTTAAAGCGACCCTGACCAAACTTGGTACAT----
9ddd2d8b6fb52157f17648682d09afda;size=1;+
TGCATTCCTATGAGAAACATGATGGGGCTTCTCTTTCCCTCATTTTTT--AGTTAGCCTTACCAAAGTTGGTACATT---
fc86d48758313be18587d6f185e5c943;size=1;+
TGCATTCCTGTGGGAAACATGAAGGGGCTTCTCTCTCCATCA-TTTTTAAAGCGACCCTGATCAAATTTGGTACAT----
243a5acbee6cd9cd223252a8bb65667e;size=1;+
TGCATTCCTATGGGAAACATGAAAGGGTTTCTCTCTCCCTCG-TTTTAAAAGCGACCCTGTCCAAACATGGTACAT----
55e50e131ec21fce8021f22de49bb7be;size=1;+
TGCATTCCAATGGGAAACATGAAAGGGCTTCTCTCTCCCTCG-TTTTTAAAGCGACCCTGTCCAAACTTGGTACAT----
For this final cluster it’s really hard to call by eye, that’s why we make the computer do it!
Step 4: Joint estimation of heterozygosity and error rate
In this step we jointly estimate sequencing error rate and heterozygosity to help us figure out which reads are “real” and which include sequencing error. We need to know which reads are “real” because in diploid organisms there are a maximum of 2 alleles at any given locus. If we look at the raw data and there are 5 or ten different “alleles”, and 2 of them are very high frequency, and the rest are singletons then this gives us evidence that the 2 high frequency alleles are good reads and the rest are probably junk. This step is pretty straightforward, and pretty fast. Run it like this:
$ cd ipyrad-workshop
$ ipyrad -p params-peddrad.txt -s 4 -c 1
loading Assembly: peddrad
from saved path: ~/ipyrad-workshop/peddrad.json
-------------------------------------------------------------
ipyrad [v.0.9.59]
Interactive assembly and analysis of RAD-seq data
-------------------------------------------------------------
Parallel connection | jupyter-dereneaton-2dipyrad-2dqk37slac: 1 cores
Step 4: Joint estimation of error rate and heterozygosity
[####################] 100% 0:00:12 | inferring [H, E]
Parallel connection closed.
In terms of results, there isn’t as much to look at as in previous steps, though
you can invoke the -r flag to see the estimated heterozygosity and error rate
per sample.
$ ipyrad -p params-peddrad.txt -r
Summary stats of Assembly peddrad
------------------------------------------------
state reads_raw reads_passed_filter refseq_mapped_reads ... clusters_hidepth hetero_est error_est reads_consens
1A_0 4 19835 19835 19835 ... 1000 0.001842 0.000773 1000
1B_0 4 20071 20071 20071 ... 1000 0.001861 0.000751 1000
1C_0 4 19969 19969 19969 ... 1000 0.002045 0.000761 1000
1D_0 4 20082 20082 20082 ... 1000 0.001813 0.000725 1000
2E_0 4 20004 20004 20004 ... 1000 0.002006 0.000767 1000
2F_0 4 19899 19899 19899 ... 1000 0.002045 0.000761 1000
2G_0 4 19928 19928 19928 ... 1000 0.001858 0.000765 1000
2H_0 4 20110 20110 20110 ... 1000 0.002129 0.000730 1000
3I_0 4 20078 20078 20078 ... 1000 0.001961 0.000749 1000
3J_0 4 19965 19965 19965 ... 1000 0.001950 0.000748 1000
3K_0 4 19846 19846 19846 ... 1000 0.001959 0.000768 1000
3L_0 4 20025 20025 20025 ... 1000 0.001956 0.000753 1000
Illumina error rates are on the order of 0.1% per base, so your error rates will ideally be in this neighborhood. Also, under normal conditions error rate will be much, much lower than heterozygosity (on the order of 10x lower). If the error rate is » 0.1% then you might be using too permissive a clustering threshold. Just a thought.
Step 5: Consensus base calls
Step 5 uses the inferred error rate and heterozygosity per sample to call the consensus of sequences within each cluster. Here we are identifying what we believe to be the real haplotypes at each locus within each sample.
$ ipyrad -p params-peddrad.txt -s 5 -c 1
loading Assembly: peddrad
from saved path: ~/ipyrad-workshop/peddrad.json
-------------------------------------------------------------
ipyrad [v.0.9.59]
Interactive assembly and analysis of RAD-seq data
-------------------------------------------------------------
Parallel connection | jupyter-dereneaton-2dipyrad-2dqk37slac: 1 cores
Step 5: Consensus base/allele calling
Mean error [0.00075 sd=0.00001]
Mean hetero [0.00195 sd=0.00010]
[####################] 100% 0:00:01 | calculating depths
[####################] 100% 0:00:00 | chunking clusters
[####################] 100% 0:01:03 | consens calling
[####################] 100% 0:00:03 | indexing alleles
Parallel connection closed.
In-depth operations of step 5:
- calculating depths - A simple refinement of the H/E estimates
- chunking clusters - Again, breaking big files into smaller chunks to aid parallelization
- consensus calling - Actually perform the consensus sequence calling
- indexing alleles - Cleaning up and re-joining chunked data
$ ipyrad -p params-peddrad.txt -r
loading Assembly: peddrad
from saved path: ~/ipyrad-workshop/peddrad.json
Summary stats of Assembly peddrad
------------------------------------------------
state reads_raw reads_passed_filter refseq_mapped_reads ... clusters_hidepth hetero_est error_est reads_consens
1A_0 5 19835 19835 19835 ... 1000 0.001842 0.000773 1000
1B_0 5 20071 20071 20071 ... 1000 0.001861 0.000751 1000
1C_0 5 19969 19969 19969 ... 1000 0.002045 0.000761 1000
1D_0 5 20082 20082 20082 ... 1000 0.001813 0.000725 1000
2E_0 5 20004 20004 20004 ... 1000 0.002006 0.000767 1000
2F_0 5 19899 19899 19899 ... 1000 0.002045 0.000761 1000
2G_0 5 19928 19928 19928 ... 1000 0.001858 0.000765 1000
2H_0 5 20110 20110 20110 ... 1000 0.002129 0.000730 1000
3I_0 5 20078 20078 20078 ... 1000 0.001961 0.000749 1000
3J_0 5 19965 19965 19965 ... 1000 0.001950 0.000748 1000
3K_0 5 19846 19846 19846 ... 1000 0.001959 0.000768 1000
3L_0 5 20025 20025 20025 ... 1000 0.001956 0.000753 1000
And here the important information is the number of reads_consens. This is
the number of retained reads within each sample that we’ll send on to the next
step. Retained reads must pass filters on read depth tolerance (both
mindepth_majrule and maxdepth), maximum number of uncalled bases
(max_Ns_consens) and maximum number of heterozygous sites (max_Hs_consens)
per consensus sequence. This number will almost always be lower than
clusters_hidepth.
Step 6: Cluster across samples
Step 6 clusters consensus sequences across samples. Now that we have good estimates for haplotypes within samples we can try to identify similar sequences at each locus among samples. We use the same clustering threshold as step 3 to identify sequences among samples that are probably sampled from the same locus, based on sequence similarity.
Note on performance of each step: Steps 3 and 6 generally take considerably longer than any of the steps, due to the resource intensive clustering and alignment phases. These can take on the order of 10-100x as long as the next longest running step. Fortunately, with the simulated data, step 6 will actually be really fast.
$ ipyrad -p params-peddrad.txt -s 6 -c 1
loading Assembly: peddrad
from saved path: ~/ipyrad-workshop/peddrad.json
-------------------------------------------------------------
ipyrad [v.0.9.59]
Interactive assembly and analysis of RAD-seq data
-------------------------------------------------------------
Parallel connection | jupyter-dereneaton-2dipyrad-2dpnwm5vfx: 1 cores
Step 6: Clustering/Mapping across samples
[####################] 100% 0:00:01 | concatenating inputs
[####################] 100% 0:00:04 | clustering across
[####################] 100% 0:00:00 | building clusters
[####################] 100% 0:00:35 | aligning clusters
Parallel connection closed.
In-depth operations of step 6:
- concatenating inputs - Gathering all consensus files and preprocessing to improve performance.
- clustering across - Cluster by similarity threshold across samples
- building clusters - Group similar reads into clusters
- aligning clusters - Align within each cluster
Since in general the stats for results of each step are sample based, the output
of -r will only display what we had seen after step 5, so this is not that
informative.
It might be more enlightening to consider the output of step 6 by examining the file that contains the reads clustered across samples:
$ cat peddrad_across/peddrad_clust_database.fa | head -n 27
#1A_0,@1B_0,@1C_0,@1D_0,@2E_0,@2F_0,@2G_0,@2H_0,@3I_0,@3J_0,@3K_0,@3L_0
>1A_0_11
TGCAGGCGTAGTAAGCTTGGATGGGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTGATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>1B_0_16
TGCAGGCGTAGTAAGCTTGGATGGGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTGATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>1C_0_678
TGCAGGCGTAGTAAGCTTGCATGGGAGCGACCACCCGAACGAGATATCAATCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTGATATACGWATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>1D_0_509
TGCAGGCGTAGTAAGCTTGCATGGGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTGATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>2E_0_859
TGCAGGCGTAGTAAGCTTGCATGGGAGCGACCWCCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTGATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>2F_0_533
TGCAGGCGTAGTAAGCTTGCATGGGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTGATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>2G_0_984
TGCAGGCGTAGTAAGCTTGCATGGGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTGATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>2H_0_529
TGCAGGCGTAGTAAGCTTGCATGGGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTGATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>3I_0_286
TGCAGGCGTAGTAAGCTTGCATGCGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTTATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>3J_0_255
TGCAGGCGTAGTAAGCTTGCATGCGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTTATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>3K_0_264
TGCAGGCGTAGTAAGCTTGCATGCGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTTATATACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
>3L_0_865
TGCAGGCGTAGTAAGCTTGCATGCGAGCGACCACCCGAACGAGATATCATTCACAACGTTATACATACACTGCGCnnnnCCATTATATGGTGTTATAYACGTATCCTCAAACCGAATTACAAAACGATGTGCTTACGGCGTAATCTTGGTCCCG
//
//
Again, the simulated data are a little boring. Here’s something you might see more typically with real data:
punc_IBSPCRIB0361_10
TdGCATGCAACTGGAGTGAGGTGGTTTGCATTGATTGCTGTATATTCAATGCAAGCAACAGGAATGAAGTGGATTTCTTTGGTCACTATATACTCAATGCA
punc_IBSPCRIB0361_1647
TGCATGCAACAGGAGTGANGTGrATTTCTTTGRTCACTGTAyANTCAATGYA
//
//
punc_IBSPCRIB0361_100
TGCATCTCAACGTGGTCTCGTCACATTTCAAGGCGCACATCAGAATGCAGTACAATAATCCCTCCCCAAATGCA
punc_MUFAL9635_687
TGCATCTCAACATGGTCTCGTCACATTTCAAGGCGCACATCAGAATGCAGTACAATAATCCCTCCCCAAATGCA
punc_ICST764_3619
TGCATCTCAACGTGGTCTCGTCACATTTCAAGGCGCACATCAGAATGCAGTACAATAATCCCTCCCCAAATGCA
punc_JFT773_4219
TGCATCTCAACGTGGTCTCGTCACATTTCAAGGCGCACATCAGAATGCAGTACAATAATCCCTCCCCAAATGCA
punc_MTR05978_111
TGCATCTCAACGTGGTCTCGTCACATTTCAAGGCGCACATCAGAATGCAGTACAATAATCCCTCCCCAAATGCA
punc_MTR17744_1884
TGCATCTCAACGTGGTCTCGTCACATTTCAAGGCGCACATCAGAATGCA-------------------------
punc_MTR34414_3503
TGCATCTCAACGTGGTCTCGTCACATTTCAAGGCGCACATCAGAATGCAGTACAATAATCCCTCCCCAAATGCA
//
//
punc_IBSPCRIB0361_1003
TGCATAATGGACTTTATGGACTCCATGCCGTCGTTGCACGTACCGTAATTGTGAAATGCAAGATCGGGAGCGGTT
punc_MTRX1478_1014
TGCATAATGGACTTTATGGACTCCATGCCGTCGTTGCACGTACCGTAATTGTGAAATGCA---------------
//
//
The final output of step 6 is a file in peddrad_across called
peddrad_clust_database.fa. This file contains all aligned reads across all
samples. Executing the above command you’ll see all the reads that align at
each locus. You’ll see the sample name of each read followed by the sequence of
the read at that locus for that sample. If you wish to examine more loci you
can increase the number of lines you want to view by increasing the value you
pass to head in the above command (e.g. ... | head -n 300).
Step 7: Filter and write output files
The final step is to filter the data and write output files in many convenient file formats. First, we apply filters for maximum number of indels per locus, max heterozygosity per locus, max number of snps per locus, and minimum number of samples per locus. All these filters are configurable in the params file. You are encouraged to explore different settings, but the defaults are quite good and quite conservative.
To run step 7:
$ ipyrad -p params-peddrad.txt -s 7 -c 1
loading Assembly: peddrad
from saved path: ~/ipyrad-workshop/peddrad.json
-------------------------------------------------------------
ipyrad [v.0.9.59]
Interactive assembly and analysis of RAD-seq data
-------------------------------------------------------------
Parallel connection | jupyter-dereneaton-2dipyrad-2dpnwm5vfx: 1 cores
Step 7: Filtering and formatting output files
[####################] 100% 0:00:07 | applying filters
[####################] 100% 0:00:02 | building arrays
[####################] 100% 0:00:01 | writing conversions
Parallel connection closed.
In-depth operations of step 7:
- applying filters - Apply filters for max # indels, SNPs, & shared hets, and minimum # of samples per locus
- building arrays - Construct the final output data in hdf5 format
- writing conversions - Write out all designated output formats
Step 7 generates output files in the peddrad_outfiles directory. All the
output formats specified by the output_formats parameter will be generated
here. Let’s see what’s created by default:
$ ls peddrad_outfiles/
peddrad.loci peddrad.phy peddrad.seqs.hdf5 peddrad.snps peddrad.snps.hdf5 peddrad.snpsmap peddrad_stats.txt
ipyrad always creates the peddrad.loci file, as this is our internal format,
as well as the peddrad_stats.txt file, which reports final statistics for the
assembly (more below). The other files created fall in to 2 categories: files
that contain the full sequence (i.e. the peddrad.phy and peddrad.seqs.hdf5
files) and files that contain only variable sites (i.e. the peddrad.snps and
peddrad.snps.hdf5 files). The peddrad.snpsmap is a file which maps SNPs to
loci, which is used downstream in the analysis toolkit for sampling unlinked
SNPs.
The most informative, human-readable file here is peddrad_stats.txt which
gives extensive and detailed stats about the final assembly. A quick overview
of the different sections of this file:
$ cat peddrad_outfiles/peddrad_stats.txt
## The number of loci caught by each filter.
## ipyrad API location: [assembly].stats_dfs.s7_filters
total_filters applied_order retained_loci
total_prefiltered_loci 0 0 1000
filtered_by_rm_duplicates 0 0 1000
filtered_by_max_indels 0 0 1000
filtered_by_max_SNPs 0 0 1000
filtered_by_max_shared_het 0 0 1000
filtered_by_min_sample 0 0 1000
total_filtered_loci 0 0 1000
This block indicates how filtering is impacting your final dataset. Each filter
is applied in order from top to bottom, and the number of loci removed because
of each filter is shown in the applied_order column. The total number of
retained_loci after each filtering step is displayed in the final column.
This is a good place for inspecting how your filtering thresholds are impacting
your final dataset. For example, you might see that most loci are being filterd
by min_sample_locus (a very common result), in which case you might reduce
this threshold in your params file and re-run step 7 in order to retain more loci. You can use branching, so you can re-run part of the analysis, without overwriting the output you already generated.
The next block shows a simple summary of the number of loci retained for each sample in the final dataset. Pretty straightforward. If you have some samples that have very low sample_coverage here it might be good to remove them and re-run step 7. Also this can be done by using branching.
## The number of loci recovered for each Sample.
## ipyrad API location: [assembly].stats_dfs.s7_samples
sample_coverage
1A_0 1000
1B_0 1000
1C_0 1000
1D_0 1000
2E_0 1000
2F_0 1000
2G_0 1000
2H_0 1000
3I_0 1000
3J_0 1000
3K_0 1000
3L_0 1000
The next block is locus_coverage, which indicates the number of loci that
contain exactly a given number of samples, and sum_coverage is just the
running total of these in ascending order. So here, if it weren’t being
filtered, locus coverage in the 1 column would indicate singletons (only
one sample at this locus), and locus coverage in the 10 column indicates
loci with full coverage (all samples have data at these loci).
Note: It’s important to notice that locus coverage below your
min_sample_locusparameter setting will all naturally equal 0, since by definition these are being removed.
## The number of loci for which N taxa have data.
## ipyrad API location: [assembly].stats_dfs.s7_loci
locus_coverage sum_coverage
1 0 0
2 0 0
3 0 0
4 0 0
5 0 0
6 0 0
7 0 0
8 0 0
9 0 0
10 0 0
11 0 0
12 1000 1000
Whereas the previous block indicated samples per locus, below we are looking at
SNPs per locus. In a similar fashion as above, these columns record the counts
of loci containing given numbers of variable sites and parsimony informative
sites (pis). For example, in the 2 row, this indicates the number of loci
with 2 variable sites (174), and the number of loci with 2 pis (48). The sum_*
columns simply indicate the running total in ascending order.
Note: This block can be a little tricky because loci can end up getting double-counted. For example, a locus with 1 pis, and 2 autapomorphies will be counted once in the 3 row for
var, and once in the 1 row forpis. Apply care when interpreting these values.
The distribution of SNPs (var and pis) per locus.
## var = Number of loci with n variable sites (pis + autapomorphies)
## pis = Number of loci with n parsimony informative site (minor allele in >1 sample)
## ipyrad API location: [assembly].stats_dfs.s7_snps
## The "reference" sample is included if present unless 'exclude_reference=True'
var sum_var pis sum_pis
0 1 0 163 0
1 5 5 288 288
2 20 45 264 816
3 46 183 160 1296
4 66 447 70 1576
5 111 1002 36 1756
6 164 1986 13 1834
7 141 2973 5 1869
8 122 3949 1 1877
9 121 5038 0 1877
10 76 5798 0 1877
11 57 6425 0 1877
12 30 6785 0 1877
13 14 6967 0 1877
14 15 7177 0 1877
15 4 7237 0 1877
16 3 7285 0 1877
17 4 7353 0 1877
The next block displays statistics for each sample in the final dataset.
Many of these stats will already be familiar, but this provides a nice compact
view on how each sample is represented in the output. The one new stat here is
loci_in_assembly, which indicates how many loci each sample has data for.
## Final Sample stats summary
state reads_raw reads_passed_filter refseq_mapped_reads refseq_unmapped_reads clusters_total clusters_hidepthhetero_est error_est reads_consens loci_in_assembly
1A_0 7 19835 19835 19835 0 1000 1000 0.001842 0.000773 1000 1000
1B_0 7 20071 20071 20071 0 1000 1000 0.001861 0.000751 1000 1000
1C_0 7 19969 19969 19969 0 1000 1000 0.002045 0.000761 1000 1000
1D_0 7 20082 20082 20082 0 1000 1000 0.001813 0.000725 1000 1000
2E_0 7 20004 20004 20004 0 1000 1000 0.002006 0.000767 1000 1000
2F_0 7 19899 19899 19899 0 1000 1000 0.002045 0.000761 1000 1000
2G_0 7 19928 19928 19928 0 1000 1000 0.001858 0.000765 1000 1000
2H_0 7 20110 20110 20110 0 1000 1000 0.002129 0.000730 1000 1000
3I_0 7 20078 20078 20078 0 1000 1000 0.001961 0.000749 1000 1000
3J_0 7 19965 19965 19965 0 1000 1000 0.001950 0.000748 1000 1000
3K_0 7 19846 19846 19846 0 1000 1000 0.001959 0.000768 1000 1000
3L_0 7 20025 20025 20025 0 1000 1000 0.001956 0.000753 1000 1000
The final block displays some very brief, but informative, summaries of missingness in the assembly at both the sequence and the SNP level:
## Alignment matrix statistics:
sequence matrix size: (12, 148725), 0.00% missing sites.
snps matrix size: (12, 7353), 0.00% missing sites.
For some downstream analyses we might need more than just the default output
formats, so lets rerun step 7 and generate all supported output formats. This
can be accomplished by editing the params-peddrad.txt file and setting the
requested output_formats to * (again, the wildcard character):
* ## [27] [output_formats]: Output formats (see docs)
After this we must now re-run step 7, but this time including the -f flag,
to force overwriting the output files that were previously generated. More
information about all supported output formats can be found in the ipyrad docs.
$ ipyrad -p params-peddrad.txt -s 7 -c 1 -f
And now you can see the numerous new output formats that have been created:
$ ls peddrad_outfiles/
peddrad.alleles peddrad.loci peddrad.phy peddrad.snps.hdf5 peddrad.str peddrad.usnps
peddrad.geno peddrad.migrate peddrad.seqs.hdf5 peddrad.snpsmap peddrad.treemix peddrad.ustr
peddrad.gphocs peddrad.nex peddrad.snps peddrad_stats.txt peddrad.ugeno peddrad.vcf
Congratulations! You’ve completed your first RAD-Seq assembly. Now you can try
applying what you’ve learned to assemble your own real data. Please consult the
ipyrad online documentation for details about
many of the more powerful features of ipyrad, including reference sequence
mapping, assembly branching, and the extensive analysis toolkit, which
includes extensive downstream analysis tools for such things as clustering and
population assignment, phylogenetic tree inference, quartet-based species tree
inference, and much more.