def add_reference_sequence(ref: hl.ReferenceGenome) -> hl.ReferenceGenome:
"""
Adds the fasta sequence to a Hail reference genome.
Only GRCh37 and GRCh38 references are supported.
:param ref: Input reference genome.
:return:
"""
if not ref.has_sequence():
if ref.name == "GRCh38":
ref.add_sequence(
"file:///home/ubuntu/data/resources/hail-common/references/Homo_sapiens_assembly38.fasta.gz",
"file:///home/ubuntu/data/resources/hail-common/references/Homo_sapiens_assembly38.fasta.fai",
)
elif ref.name == "GRCh37":
ref.add_sequence(
"file:///home/ubuntu/data/resources/hail-common/references/human_g1k_v37.fasta.gz",
"file:///home/ubuntu/data/resources/hail-common/references/human_g1k_v37.fasta.fai",
)
else:
raise NotImplementedError(
f"No known location for the fasta/fai files for genome {ref.name}. Only GRCh37 and GRCh38 are supported at this time."
)
else:
logger.info(
"Reference genome sequence already present. Ignoring add_reference_sequence."
)
return ref
def get_reference_ht(
ref: hl.ReferenceGenome,
contigs: Optional[List[str]] = None,
excluded_intervals: Optional[List[hl.Interval]] = None,
add_all_substitutions: bool = False,
filter_n: bool = True,
) -> hl.Table:
"""
Creates a reference Table with locus and alleles (containing only the reference allele by default) from the given reference genome.
.. note::
If the `contigs` argument is not provided, all contigs (including obscure ones) will be added to the table.
This can be slow as contigs are added one by one.
:param ref: Input reference genome
:param contigs: An optional list of contigs that the Table should include
:param excluded_intervals: An optional list of intervals to exclude
:param add_all_substitutions: If set, then all possible substitutions are added in the alleles array
:param filter_n: If set, bases where the reference is unknown (n) are filtered.
:return:
"""
if not ref.has_sequence():
add_reference_sequence(ref)
if not contigs:
contigs = ref.contigs
if add_all_substitutions:
SUBSTITUTIONS_TABLE = hl.literal(
{
"a": ["c", "g", "t"],
"c": ["a", "g", "t"],
"g": ["a", "c", "t"],
"t": ["a", "c", "g"],
}
)
context = []
for contig in contigs:
n_partitions = max(1, int(ref.contig_length(contig) / 5000000))
logger.info(
f"Creating reference contig {contig} with {n_partitions} partitions."
)
_context = hl.utils.range_table(
ref.contig_length(contig), n_partitions=n_partitions
)
locus_expr = hl.locus(contig=contig, pos=_context.idx + 1, reference_genome=ref)
ref_allele_expr = locus_expr.sequence_context().lower()
if add_all_substitutions:
alleles_expr = hl.array([ref_allele_expr]).extend(
SUBSTITUTIONS_TABLE.get(ref_allele_expr, hl.empty_array(hl.tstr))
)
else:
alleles_expr = [ref_allele_expr]
_context = (
_context.select(locus=locus_expr, alleles=alleles_expr)
.key_by("locus", "alleles")
.drop("idx")
)
if excluded_intervals is not None:
_context = hl.filter_intervals(_context, excluded_intervals, keep=False)
if filter_n:
_context = _context.filter(_context.alleles[0] == "n", keep=False)
context.append(_context)
return context.pop().union(*context)