GenRecord.py

"""
Module to convert a GenBank record to a nested dictionary consisting of
a list of genes, which itself consists of a list of loci. This structure
makes it possible to iterate over genes and transcripts without having to
search for them each time.

@requires: Crossmap
@requires: Bio
@requires: Db
"""
# Public classes:
#     - PList     ; Store a general location and a list of splice sites.
#     - Locus     ; Store data about the mRNA and CDS splice sites.
#     - Gene      ; Store a list of Locus objects and the orientation.
#     - Record    ; Store a geneList and other additional information.
#     - GenRecord ; Convert a GenBank record to a nested dictionary.


import Bio

from mutalyzer import util
from mutalyzer import config
from mutalyzer import Crossmap
from mutalyzer import Db


class PList(object) :
    """
    A position list object, to store a general location and a list of
    specific splice sites (if available).

    These objects are used to describe either a list of mRNA splice sites
    or a list of CDS splice sites. These splice sites are stored in the
    list element. The location element is a fallback in case the splice
    sites are not available.

    Special methods:
        - __init__() ; Initialise the class.

    Public variables:
        - location ; A tuple of integers between which the object resides.
        - list     ; A list (with an even amount of entries) of splice sites.
    """

    def __init__(self) :
        """
        Initialise the class.

        Public variables (altered):
            - location     ; A tuple of integers between which the object
                             resides.
            - POSITIONlist ; A list (with an even amount of entries) of splice
                             sites.
        """

        self.location = []
        self.positionList = []
    #__init__
#PList

class Locus(object) :
    """
    A Locus object, to store data about the mRNA and CDS splice sites.

    Special methods:
        - __init__() ; Initialise the class.

    Public variables:
        - mRNA ; A position list object.
        - CDS  ; A position list object.
        - exon ; A position list object.
    """

    def __init__(self, name) :
        """
        Initialise the class.

        Public variables (altered):
            - mRNA     ; A position list object.
            - CDS      ; A position list object.
            - location ;
            - exon     ; A position list object.
            - txTable  ; The translation table.
            - CM       ; A Crossmap object.

        @arg name: identifier of the locus
        @type name: string
        """

        self.name = name
        self.current = False
        self.mRNA = None
        self.CDS = None
        self.location = []
        self.exon = None
        self.txTable = 1
        self.CM = None
        self.transcriptID = None
        self.proteinID = None
        self.genomicID = None
        self.molType = 'c'
        self.description = ""
        self.proteinDescription = "?"
        self.proteinRange = []
        self.locusTag = None
        self.link = None
        self.transcribe = False
        self.translate = False
        self.linkMethod = None
        self.transcriptProduct = None
        self.proteinProduct = None
    #__init__

    def cancelDescription(self):
        """
        Set the description on this locus to 'unknown'.

        This can be used if at some point we give up creating a sensible
        description on this locus. It also makes sure future additions to
        the description are ignored and it keeps the 'unknown' value.

        @note: This depends on the check for the unknown value in the
            addToDescription method. This is a not a beatiful solution.
        """
        self.description = '?'
    #cancelDescription

    def addToDescription(self, rawVariant):
        """
        Expands the DNA description with a new raw variant.

        @arg rawVariant: description of a single mutation
        @type rawVariant: string
        """
        if self.description:
            # Don't change anything if we already have an unknown value.
            if self.description != '?':
                self.description = "%s;%s" % (self.description, rawVariant)
        else:
            self.description = rawVariant
    #addToDescription
#Locus


class Gene(object) :
    """
    A Gene object, to store a list of Locus objects and the orientation of
    the gene.

    Special methods:
        - __init__() ; Initialise the class.

    Public variables:
        - orientation; The orientation of the gene: 1 = forward, -1 = reverse.
        - transcriptslist; A list of Locus objects.
    """

    def __init__(self, name) :
        """
        Initialise the class.

        Public variables (altered):
            - name
            - orientation    ; The orientation of the gene.
            - transcriptList ; A list of transcripts
            - location ;
            - longName ;
        Private variables (altered):
            - __locusTag ;

        @arg name: gene name
        @type name: string
        """

        self.name = name
        self.orientation = 1
        self.transcriptList = []
        self.location = []
        self.longName = ""
        self.__locusTag = "000"
    #__init__

    def newLocusTag(self) :
        """
        Generates a new Locus tag.

        @return: Locus tag
        @rtype: integer (3 digits, if < 100 preceeded with 0's)
        """

        self.__locusTag = "%03i" % (int(self.__locusTag) + 1)

        return self.__locusTag
    #newLocusTag

    def findLocus(self, name) :
        """
        Find a transcript, given its name.

        @arg name: transcript variant number
        @type name: string

        @return: transcript
        @rtype: object
        """

        for i in self.transcriptList :
            if i.name == name or i.name == str("%03i" % int(name)):
                return i
        return None
    #findLocus

    def listLoci(self) :
        """
        Provides a list of transcript variant numbers

        @return: list of transcript variant numbers
        @rtype: list
        """

        ret = []
        for i in self.transcriptList :
            ret.append(i.name)
        return ret
    #listLoci

    def findLink(self, protAcc) :
        """
        Look in the list of transcripts for a given protein accession number.

        @arg protAcc: protein accession number
        @type protAcc: string

        @return: transcript
        @rtype: object
        """

        for i in self.transcriptList :
            if i.link == protAcc :
                return i
        return None
    #findLink
#Gene

class Record(object) :
    """
    A Record object, to store a geneList and other additional
    information.

    Special methods:
        - __init__() ; Initialise the class.

    Public variables:
        - geneList  ; List of Gene objects.
        - mol_type  ; Variable to indicate the sequence type (DNA, RNA, ...)
        - organelle ; Variable to indicate whether the sequence is from the
                      nucleus or from an organelle (if so, also from which
                      one).
        - source    ; A fake gene that can be used when no gene information
                      is present.
    """

    def __init__(self) :
        """
        Initialise the class.


        Public variables (altered):
            - geneList  ; List of Gene objects.
            - molType   ; Variable to indicate the sequence type (DNA, RNA,
                          ...)
            - seq       ; The reference sequence
            - mapping   ; The mapping of the reference sequence to the genome
                          include a list of differences between the sequences
            - organelle ; Variable to indicate whether the sequence is from
                          the nucleus or from an organelle (if so, also from
                          which one).
            - source    ; A fake gene that can be used when no gene
                          information is present.
        """

        self.geneList = []
        self.molType = 'g'
        self.seq = ""
        self.mapping = []
        self.organelle = None
        self.source = Gene(None)
        self.description = ""
        self._sourcetype = None           #LRG or GB
        self.version = None
        self.chromOffset = 0
        self.chromDescription = ""
        self.orientation = 1
        self.recordId = None
    #__init__

    def findGene(self, name) :
        """
        Returns a Gene object, given its name.

        @arg name: Gene name
        @type name: string

        @return: Gene object
        @rtype: object
        """

        for i in self.geneList :
            if i.name == name :
                return i
        return None
    #findGene

    def listGenes(self) :
        """
        List the names of all genes found in this record.

        @return: Genes list
        @rtype: list

        """

        ret = []
        for i in self.geneList :
            ret.append(i.name)
        return ret
    #listGenes

    def addToDescription(self, rawVariant) :
        """
        Expands the DNA description with a new raw variant.

        @arg rawVariant: description of a single mutation
        @type rawVariant: string
        """

        if self.description :
            self.description = "%s;%s" % (self.description, rawVariant)
        else :
            self.description = rawVariant
    #addToDescription

    def toChromPos(self, i) :
        """
        Converts a g. position (relative to the start of the record) to a
        chromosomal g. position

        @arg i: g. position (relative to the start of the record)
        @type i: integer

        @return: chromosomal g. position
        @rtype: integer
        """
        if not self.chromOffset:
            return None

        if self.orientation == 1 :
            return self.chromOffset + i - 1
        return self.chromOffset - i + 1
    #toChromPos

    def addToChromDescription(self, rawVariant) :
        """
        @todo document me
        """

        if not self.chromOffset :
            return
        if self.chromDescription :
            self.chromDescription = "%s;%s" % (self.chromDescription,
                rawVariant)
        else :
            self.chromDescription = rawVariant
    #addToChromDescription
#Record

class GenRecord() :
    """
    Convert a GenBank record to a nested dictionary.

    Public methods:
        - checkRecord()   ;   Check and repair self.record.
    """

    def __init__(self, output) :
        """
        Initialise the class.

        Public variable:
            - record    ; A record object

        @arg output: an output object
        @type output: object
        """
        self.__output = output
        self.record = None
    #__init__

    def __checkExonList(self, exonList, CDSpos) :
        """
        @todo document me

        @arg exonList: list of splice sites
        @type exonList: list (object)
        @arg CDSpos: location of the CDS
        @type CDSpos: object

        @return:
        @rtype: boolean
        """

        if not exonList :
            return False
        if not CDSpos :
            return True

        e = exonList.positionList
        c = CDSpos.location

        seen = 0
        for i in range(0, len(e), 2) :
            if e[i] <= c[0] and e[i + 1] >= c[0] :
                seen += 1
            if e[i] <= c[1] and e[i + 1] >= c[1] :
                seen += 1
        #for

        if seen == 2 :
            return True
        return False
    #__checkExonList

    def __constructCDS(self, mRNA, CDSpos) :
        """
        Construct a list of coordinates that contains CDS start and stop and
        the internal splice sites.

        @arg mRNA: mRNA positions/coordinates list
        @type mRNA: list (integer)
        @arg CDSpos: coding DNA positions/coordinates
        @type CDSpos: list (integer)

        @return: CDS positions plus internal splice sites
        @rtype: list (integer)
        """

        i = 1
        ret = [CDSpos[0]]

        while CDSpos[0] > mRNA[i] :
            i += 2

        j = i
        while CDSpos[1] > mRNA[j] :
            j += 2

        ret.extend(mRNA[i:j])
        ret.append(CDSpos[1])

        return ret
    #__constructCDS

    def __maybeInvert(self, gene, string, string_reverse=None) :
        """
        Return the reverse-complement of a DNA sequence if the gene is in
        the reverse orientation.

        @arg gene: Gene
        @type gene: object
        @arg string: DNA sequence
        @type string: string
        @kwarg string_reverse: DNA sequence to use (if not None) for the
            reverse complement.

        @return: reverse-complement (if applicable), otherwise return the
            original.
        @rtype: string
        """
        if gene.orientation == -1:
            if string_reverse:
                string = string_reverse
            return Bio.Seq.reverse_complement(string)
        return string
    #__maybeInvert

    def checkRecord(self) :
        """
        Check if the record in self.record is compatible with mutalyzer.
        Update the mRNA PList with the exon and CDS data.

        @todo: This function should really check the record for minimal
        requirements
        """

        #TODO:  This function should really check
        #       the record for minimal requirements.
        for i in self.record.geneList :
            """
            if len(i.transcriptList) == 2 :
                if i.transcriptList[0].CDS and not i.transcriptList[1].CDS and \
                   i.transcriptList[1].mRNA and not i.transcriptList[0].mRNA :
                    i.transcriptList[0].mRNA = i.transcriptList[1].mRNA
                if i.transcriptList[1].CDS and not i.transcriptList[0].CDS and \
                   i.transcriptList[0].mRNA and not i.transcriptList[1].mRNA :
                    i.transcriptList[0].CDS = i.transcriptList[1].CDS
                i.transcriptList = [i.transcriptList[0]]
                i.transcriptList[0].transcribe = True
                i.transcriptList[0].translate = True
            #if
            """
            for j in i.transcriptList :
                if not j.mRNA :
                    usableExonList = self.__checkExonList(j.exon, j.CDS)
                    if not j.exon or not usableExonList :
                        if self.record.molType == 'g' :
                            self.__output.addMessage(__file__, 2, "WNOMRNA",
                                "No mRNA field found for gene %s, transcript " \
                                "variant %s in record, constructing " \
                                "it from CDS. Please note that descriptions "\
                                "exceeding CDS boundaries are invalid." % (
                                i.name, j.name))
                        if j.exon and j.exon.positionList and \
                           not usableExonList :
                            self.__output.addMessage(__file__, 2, "WNOMRNA",
                                "Exons were found for gene %s, transcript " \
                                "variant %s but were not usable. " \
                                "Please note that descriptions "\
                                "exceeding CDS boundaries are invalid." % (
                                i.name, j.name))
                        if j.CDS :
                            if not j.CDS.positionList :
                                #self.__output.addMessage(__file__, 2,
                                #    "WNOCDSLIST", "No CDS list found for " \
                                #    "gene %s, transcript variant %s in " \
                                #    "record, constructing it from " \
                                #    "CDS location." % (i.name, j.name))
                                j.mRNA = j.CDS
                                j.mRNA.positionList = j.CDS.location
                            #if
                            else :
                                j.mRNA = j.CDS
                            j.linkMethod = "construction"
                            j.transcribe = True
                            j.translate = True
                        #if
                        else :
                            self.__output.addMessage(__file__, 2, "WNOCDS",
                                "No CDS found for gene %s, transcript " \
                                "variant %s in record, " \
                                "constructing it from gene location." % (
                                i.name, j.name))
                            j.CDS = None #PList()
                            #j.CDS.location = i.location
                            j.mRNA = PList()
                            j.mRNA.location = i.location
                            #j.mRNA.positionList = i.location
                            j.molType = 'n'
                        #else
                    #if
                    else :
                        #self.__output.addMessage(__file__, 2, "WNOMRNA",
                        #    "No mRNA field found for gene %s, transcript " \
                        #    "variant %s in record, constructing " \
                        #    "it from gathered exon information." % (
                        #    i.name, j.name))
                        j.mRNA = j.exon
                    #else
                #if
                #else :
                #    j.transcribe = True

                if not j.mRNA.positionList :
                    j.mRNA.positionList = j.mRNA.location
                if j.mRNA.positionList and j.CDS and j.CDS.positionList != None :
                    if not j.CDS.positionList :
                        #self.__output.addMessage(__file__, 2, "WNOCDS",
                        #    "No CDS list found for gene %s, transcript " \
                        #    "variant %s in record, constructing " \
                        #    "it from mRNA list and CDS location." % (i.name,
                        #    j.name))
                        if j.mRNA.positionList :
                            j.CDS.positionList = self.__constructCDS(
                                j.mRNA.positionList, j.CDS.location)
                        else :
                            j.CDS.positionList = self.__constructCDS(
                                j.mRNA.location, j.CDS.location)
                        j.transcribe = True
                        j.translate = True
                    #if
                    j.CM = Crossmap.Crossmap(j.mRNA.positionList,
                                             j.CDS.location, i.orientation)
                #if
                else :
                    j.molType = 'n'
                    if j.mRNA.positionList :
                        j.CM = Crossmap.Crossmap(j.mRNA.positionList,
                                                 [], i.orientation)
                        j.transcribe = True
                    else :
                        j.description = '?'
                #else
            #for
        #for
    #checkRecord

    def current_transcript(self):
        """
        Return the current transcript.

        @return: Current transcript if there is one, None otherwise.
        @rtype: GenRecord.Locus
        """
        for i in self.record.geneList:
            for j in i.transcriptList:
                if j.current:
                    return j
        return None
    #current_transcript

    def name(self, start_g, stop_g, varType, arg1, arg2, roll, arg1_reverse=None,
             start_fuzzy=False, stop_fuzzy=False):
        """
        Generate variant descriptions for all genes, transcripts, etc.

        @arg start_g: start position
        @type start_g: integer
        @arg stop_g: stop position
        @type stop_g: integer
        @arg varType: variant type
        @type varType: string
        @arg arg1: argument 1 of a raw variant
        @type arg1: string
        @arg arg2: argument 2 of a raw variant
        @type arg2: string
        @arg roll: ???
        @type roll: tuple (integer, integer)
        @kwarg arg1_reverse: argument 1 to be used on reverse strand
        @type arg1_reverse: string
        @kwarg start_fuzzy: Indicates if start position of variant is fuzzy.
        @type start_fuzzy: bool
        @kwarg stop_fuzzy: Indicates if stop position of variant is fuzzy.
        @type stop_fuzzy: bool
        """
        forwardStart = start_g
        forwardStop = stop_g
        reverseStart = stop_g
        reverseStop = start_g

        if self.record.orientation == 1:
            chromStart = self.record.toChromPos(start_g)
            chromStop = self.record.toChromPos(stop_g)
            chromArg1 = arg1
            chromArg2 = arg2
        else:
            chromStart = self.record.toChromPos(stop_g)
            chromStop = self.record.toChromPos(start_g)
            chromArg1 = Bio.Seq.reverse_complement(arg1)
            chromArg2 = Bio.Seq.reverse_complement(arg2)
            # Todo: Should we use arg1_reverse here?

        if roll :
            forwardStart += roll[1]
            forwardStop += roll[1]
            reverseStart -= roll[0]
            reverseStop -= roll[0]
            if chromStart is not None:
                if self.record.orientation == 1:
                    chromStart += roll[1]
                    chromStop += roll[1]
                else:
                    chromStart += roll[0]
                    chromStop += roll[0]
        #if

        if varType != "subst" :
            if forwardStart != forwardStop :
                # Todo: Fuzzy offsets to genomic positions (see bug #38).
                #
                # The genomic positioning is problematic. We would like to
                # have it in brackets (as fuzzy positions), like the above
                # g.(34299_23232)del example.
                #
                # Now consider a variant c.a-?_b+18del where only the offset
                # before the exon is unknown but the offset after the exon is
                # exact. Now a genomic description like g.(34299)_23232del
                # comes to mind, however, this notation is not allowed by the
                # HGVS grammar.
                #
                # I think all we can do is to treat both positions as fuzzy in
                # the genomic description, even if only one of them really is.
                #
                # Peter thinks the HGVS grammar should at some point be
                # updated to allow the brackets around individual locations.
                if start_fuzzy or stop_fuzzy:
                    self.record.addToDescription("(%s_%s)%s%s" % (
                        forwardStart, forwardStop, varType, arg1))
                    self.record.addToChromDescription("(%s_%s)%s%s" % (
                        chromStart, chromStop, varType, chromArg1))
                else:
                    self.record.addToDescription("%s_%s%s%s" % (
                        forwardStart, forwardStop, varType, arg1))
                    self.record.addToChromDescription("%s_%s%s%s" % (
                        chromStart, chromStop, varType, chromArg1))
            #if
            else :
                if start_fuzzy or stop_fuzzy:
                    # Todo: Current HGVS does not allow for () around single
                    # positions, only around ranges (see above and #38).
                    self.record.addToDescription("(%s)%s%s" % (
                        forwardStart, varType, arg1))
                    self.record.addToChromDescription("(%s)%s%s" % (
                        chromStart, varType, chromArg1))
                else:
                    self.record.addToDescription("%s%s%s" % (
                        forwardStart, varType, arg1))
                    self.record.addToChromDescription("%s%s%s" % (
                        chromStart, varType, chromArg1))
            #else
        #if
        else :
            if start_fuzzy or stop_fuzzy:
                # Todo: Current HGVS does not allow for () around single
                # positions, only around ranges (see above and #38).
                self.record.addToDescription("(%s)%c>%c" % (
                    forwardStart, arg1, arg2))
                self.record.addToChromDescription("(%s)%c>%c" % (
                    chromStart, chromArg1, chromArg2))
            else:
                self.record.addToDescription("%s%c>%c" % (
                    forwardStart, arg1, arg2))
                self.record.addToChromDescription("%s%c>%c" % (
                    chromStart, chromArg1, chromArg2))

        for i in self.record.geneList :
            for j in i.transcriptList :
                if j.CM :
                    orientedStart = forwardStart
                    orientedStop = forwardStop
                    if i.orientation == -1 :
                        orientedStart = reverseStart
                        orientedStop = reverseStop
                    #if

                    # Turn of translation to protein if we hit splice sites.
                    # For the current transcript, this is handled with more
                    # care in variantchecker.py.
                    if not j.current and \
                           util.over_splice_site(orientedStart, orientedStop,
                                                 j.CM.RNA):
                        j.translate = False

                    # And check whether the variant hits CDS start.
                    if j.molType == 'c' and forwardStop >= j.CM.x2g(1, 0) \
                       and forwardStart <= j.CM.x2g(3, 0) :
                        self.__output.addMessage(__file__, 2, "WSTART",
                            "Mutation in start codon of gene %s transcript " \
                            "%s." % (i.name, j.name))
                        if not j.current:
                            j.translate = False

                    # FIXME Check whether the variant hits a splice site.

                    if varType != "subst" :
                        if orientedStart != orientedStop :
                            if (start_fuzzy or stop_fuzzy) and not j.current:
                                # Don't generate descriptions on transcripts
                                # other than the current in the case of fuzzy
                                # positions.
                                j.cancelDescription()
                            else:
                                j.addToDescription("%s_%s%s%s" % (
                                    j.CM.g2c(orientedStart, start_fuzzy),
                                    j.CM.g2c(orientedStop, stop_fuzzy),
                                    varType, self.__maybeInvert(i, arg1, arg1_reverse)))
                                self.checkIntron(i, j, orientedStart)
                                self.checkIntron(i, j, orientedStop)
                        #if
                        else :
                            if start_fuzzy and not j.current:
                                # Don't generate descriptions on transcripts
                                # other than the current in the case of fuzzy
                                # positions.
                                j.cancelDescription()
                            else:
                                j.addToDescription("%s%s%s" % (
                                    j.CM.g2c(orientedStart, start_fuzzy),
                                    varType,
                                    self.__maybeInvert(i, arg1, arg1_reverse)))
                                self.checkIntron(i, j, orientedStart)
                        #else
                    #if
                    else :
                        if start_fuzzy and not j.current:
                            # Don't generate descriptions on transcripts
                            # other than the current in the case of fuzzy
                            # positions.
                            j.cancelDescription()
                        else:
                            j.addToDescription("%s%c>%c" % (
                                j.CM.g2c(orientedStart, start_fuzzy),
                                self.__maybeInvert(i, arg1, arg1_reverse),
                                self.__maybeInvert(i, arg2)))
                            self.checkIntron(i, j, orientedStart)
                    #else
                #if
            #for
        #for
    #name

    def checkIntron(self, gene, transcript, position):
        """
        Checks if a position is on or near a splice site

        @arg gene: Gene
        @type gene: object
        @arg transcript: transcript
        @type transcript: object
        @arg position: g. position
        @type position: integer
        """
        intronPos = abs(transcript.CM.g2x(position)[1])

        if intronPos :
            # It should be easy for SOAP clients to filter out all warnings
            # related to other transcripts, so we use two codes here.
            if transcript.current:
                warning = 'WSPLICE'
                str_transcript = 'transcript %s (selected)' % transcript.name
            else:
                warning = 'WSPLICE_OTHER'
                str_transcript = 'transcript %s' % transcript.name

            if intronPos <= config.get('spliceAlarm'):
                self.__output.addMessage(__file__, 2, warning,
                    "Mutation on splice site in gene %s %s." % (
                    gene.name, str_transcript))
            elif intronPos <= config.get('spliceWarn'):
                self.__output.addMessage(__file__, 2, warning,
                    "Mutation near splice site in gene %s %s." % (
                    gene.name, str_transcript))
    #checkIntron
#GenRecord