peddy 0.0.3

tools for pedigree files
------------------------

[](http://badge.fury.io/py/peddy)
[](https://travis-ci.org/brentp/peddy)

This is currently under development. It already has a nice API for dealing with pedigree files.

It currently makes it simple to extract things like:

+ parent-child pairs
+ trios
+ sibs
+ stats on number of males/females/trios/affecteds/unaffecteds
+ families.
+ families with at least N members
+ families with at least N children
+ [not yet] families with at least N generations


We are working on adding support for the following:

Given a pedigree file and a VCF file:

+ find likely sample mixups (or PED errors)
- gender mixups on X-Chrom
- family mixups by inferring relatedness with VCF

+ mendelian errors


Usage
-----

```Python
>>> from peddy import Ped, SEX, PHENOTYPE

>>> p = Ped('my.ped')
# not yet.
#>>> p.dot() # draw the pedigree with graphviz

# not yet
# find any obvious issues (3 parents, mom as male, etc).
>>> p.validate()

# number of affecteds, un, males, females, etc. (contingency table?)
>>> p.summary()

# iterable
>>> p.samples()

>>> p.samples(phenotype=PHENOTYPE.AFFECTED, sex=SEX.MALE)

# sample object
>>> s = next(p.samples())

>>> s.phenotype

>>> s.sex

>>> s.mom

>>> s.dad

>>> s.siblings

>>> s.kids
```

Quality Control
---------------

If cyvcf2 is installed, then, given a ped-file and a VCF, we can look for cases where the relationships
defined in the ped file do not match the relationships derived from the genotypes in the VCF.

```Python
>>> from peddy import Ped
>>> p = Ped('cohort.ped')
>>> p.validate('cohort.vcf.gz')
... LIST of QUESTIONABLE SAMPLES
```
If `plot=True` is sent into the validate() method. Then a plot will be created
that shows the how `peddy` classified the pairwise relations:

[](http://github.com/brentp/cyvcf2/)


By looking for the frequency of heterozygotes in the not PAR regions of
the X chromosome, we can determine gender from a VCF:

```Python
>>> from peddy import Ped
>>> p = Ped('cohort.ped')
>>> p.sex_check('cohort.vcf.gz', plot=True)
... List of all samples with number of HETs, HOMREF, HOMALT on X
```
This will also create an image like this one where we can
see a clear sample mixup.

[](http://github.com/brentp/cyvcf2/)


On creating a pedigree object (via Ped('some.ped'). Peddy will print warnings to STDERR as appropriate like:

```
pedigree warning: '101811-101811' is dad but has female gender
pedigree warning: '101897-101897' is dad but has female gender
pedigree warning: '101896-101896' is mom of self
pedigree warning: '102110-102110' is mom but has male gender
pedigree warning: '102110-102110' is mom of self
pedigree warning: '101381-101381' is dad but has female gender
pedigree warning: '101393-101393' is mom but has male gender

unknown sample: 102498-102498 in family: K34175
unknown sample: 11509-11509 in family: K567331
unknown sample: 5180-5180 in family: K8565
```