diff --git a/src/SequenceVariation.jl b/src/SequenceVariation.jl
index dc439b6..86a240a 100644
--- a/src/SequenceVariation.jl
+++ b/src/SequenceVariation.jl
@@ -33,139 +33,7 @@ struct Inapplicable end
 
 include("Edit.jl")
 include("Variant.jl")
-
-struct Variation{S <: BioSequence, T <: BioSymbol}
-    ref::S
-    edit::Edit{S, T}
-
-    function Variation{S, T}(ref::S, e::Edit{S, T}, ::Unsafe) where {S <: BioSequence, T <: BioSymbol}
-        new(ref, e)
-    end
-end
-
-function Variation{S, T}(ref::S, e::Edit{S, T}) where {S <: BioSequence, T <: BioSymbol}
-    v = Variation{S, T}(ref, e, Unsafe())
-    is_valid(v) ? v : throw(ArgumentError("Invalid variant"))
-end
-
-Variation(ref::S, edit::Edit{S, T}) where {S, T} = Variation{S, T}(ref, edit)
-
-function Variation(ref::S, edit::AbstractString) where {S<:BioSequence}
-    T = eltype(ref)
-
-    e = parse(Edit{S,T}, edit)
-    return Variation{S,T}(ref, e)
-end
-
-function Variant(ref::S, vars::Vector{Variation{S,T}}) where {S<:BioSequence, T<:BioSymbol}
-    edits = edit.(vars)
-    return Variant{S, T}(ref, edits)
-end
-
-reference(v::Variation) = v.ref
-edit(v::Variation) = v.edit
-mutation(v::Variation) = mutation(edit(v))
-BioGenerics.leftposition(v::Variation) = leftposition(edit(v))
-BioGenerics.rightposition(v::Variation) = rightposition(edit(v))
-Base.:(==)(x::Variation, y::Variation) = x.ref == y.ref && x.edit == y.edit
-Base.hash(x::Variation, h::UInt) = hash(Variation, hash((x.ref, x.edit), h))
-
-function is_valid(v::Variation)
-    isempty(v.ref) && return false
-    op = v.edit.x
-    pos = v.edit.pos
-    if op isa Substitution
-        return pos in eachindex(v.ref)
-    elseif op isa Insertion
-        return pos in 0:lastindex(v.ref)+1
-    elseif op isa Deletion
-        return pos in 1:(lastindex(v.ref)-length(op) + 1)
-    end
-end
-
-function Base.show(io::IO, x::Variation)
-    content = x.edit.x
-    pos = x.edit.pos
-    if content isa Substitution
-        print(io, x.ref[pos], pos, content.x)
-    elseif content isa Deletion
-        print(io, 'Δ', pos, '-', pos + content.len - 1)
-    elseif content isa Insertion
-        print(io, pos, content.seq)
-    else
-        print(io, pos, content.x)
-    end
-end
-
-function Base.in(v::Variation, var::Variant)
-    if v.ref != var.ref
-        error("References must be equal")
-    end
-    any(v.edit == edit for edit in var.edits)
-end
-
-function translate(var::Variation{S, T}, aln::PairwiseAlignment{S, S}) where {S, T}
-    kind = var.edit.x
-    pos = var.edit.pos
-    seq, ref = aln.seq, aln.b
-
-    # Special case: Insertions may have a pos of 0, which cannot be mapped to
-    # the seq using ref2seq
-    if iszero(pos)
-        (s, r), _ = iterate(aln)
-        (isgap(s) | isgap(r)) && return Inapplicable()
-        return Variation{S, T}(seq, Edit{S, T}(Insertion(var.edit.x), 0))
-    end
-
-    (seqpos, op) = BA.ref2seq(aln, pos)
-    if kind isa Substitution
-        # If it's a substitution, return nothing if it maps to a deleted
-        # position, or substitutes to same base.
-        op in (BA.OP_MATCH, BA.OP_SEQ_MATCH, BA.OP_SEQ_MISMATCH) || return nothing
-        seq[seqpos] == kind.x && return nothing
-        edit = Edit{S, T}(kind, seqpos)
-        return Variation{S, T}(seq, edit, Unsafe())
-    elseif kind isa Deletion
-        # If it's a deletion, return nothing if the deleted part is already missing
-        # from the new reference.
-        (stop, op2) = BA.ref2seq(aln, pos + length(kind) - 1)
-        start = seqpos + op == BA.OP_DELETE
-        start < stop && return nothing
-        edit = Edit{S, T}(Deletion(stop - start + 1), start)
-        return Variation{S, T}(seq, edit, Unsafe())
-    else
-        # If it maps directly to a symbol, just insert
-        if op in (BA.OP_MATCH, BA.OP_SEQ_MATCH, BA.OP_SEQ_MISMATCH)
-            # This happens if there is already an insertion at the position
-            if pos != lastindex(ref) && first(ref2seq(aln, pos+1)) != seqpos + 1
-                return Inapplicable()
-            else
-                edit = Edit{S, T}(Insertion(var.edit.x), seqpos)
-                return Variation{S, T}(seq, edit, Unsafe())
-            end
-        # Alternatively, it can map to a deletion. In that case, it become really
-        # tricky to talk about the "same" insertion.
-        else
-            return Inapplicable()
-        end
-    end
-end
-
-function variations(v::Variant{S,T}) where {S,T}
-    vs = Vector{Variation{S,T}}(undef, length(edits(v)))
-    for (i, e) in enumerate(edits(v))
-        vs[i] = Variation{S,T}(reference(v), e)
-    end
-    return vs
-end
-
-function refbases(v::Variation)
-    return _refbases(mutation(v), reference(v), leftposition(v))
-end
-
-function altbases(v::Variation)
-    return _altbases(mutation(v), reference(v), leftposition(v))
-end
+include("Variation.jl")
 
 export Insertion,
     Deletion,
diff --git a/src/Variation.jl b/src/Variation.jl
new file mode 100644
index 0000000..9f0ac17
--- /dev/null
+++ b/src/Variation.jl
@@ -0,0 +1,134 @@
+struct Variation{S<:BioSequence,T<:BioSymbol}
+    ref::S
+    edit::Edit{S,T}
+
+    function Variation{S,T}(
+        ref::S, e::Edit{S,T}, ::Unsafe
+    ) where {S<:BioSequence,T<:BioSymbol}
+        return new(ref, e)
+    end
+end
+
+function Variation{S,T}(ref::S, e::Edit{S,T}) where {S<:BioSequence,T<:BioSymbol}
+    v = Variation{S,T}(ref, e, Unsafe())
+    return is_valid(v) ? v : throw(ArgumentError("Invalid variant"))
+end
+
+Variation(ref::S, edit::Edit{S,T}) where {S,T} = Variation{S,T}(ref, edit)
+
+function Variation(ref::S, edit::AbstractString) where {S<:BioSequence}
+    T = eltype(ref)
+
+    e = parse(Edit{S,T}, edit)
+    return Variation{S,T}(ref, e)
+end
+
+function Variant(ref::S, vars::Vector{Variation{S,T}}) where {S<:BioSequence,T<:BioSymbol}
+    edits = edit.(vars)
+    return Variant{S,T}(ref, edits)
+end
+
+reference(v::Variation) = v.ref
+edit(v::Variation) = v.edit
+mutation(v::Variation) = mutation(edit(v))
+BioGenerics.leftposition(v::Variation) = leftposition(edit(v))
+BioGenerics.rightposition(v::Variation) = rightposition(edit(v))
+Base.:(==)(x::Variation, y::Variation) = x.ref == y.ref && x.edit == y.edit
+Base.hash(x::Variation, h::UInt) = hash(Variation, hash((x.ref, x.edit), h))
+
+function is_valid(v::Variation)
+    isempty(v.ref) && return false
+    op = v.edit.x
+    pos = v.edit.pos
+    if op isa Substitution
+        return pos in eachindex(v.ref)
+    elseif op isa Insertion
+        return pos in 0:(lastindex(v.ref) + 1)
+    elseif op isa Deletion
+        return pos in 1:(lastindex(v.ref) - length(op) + 1)
+    end
+end
+
+function Base.show(io::IO, x::Variation)
+    content = x.edit.x
+    pos = x.edit.pos
+    if content isa Substitution
+        print(io, x.ref[pos], pos, content.x)
+    elseif content isa Deletion
+        print(io, 'Δ', pos, '-', pos + content.len - 1)
+    elseif content isa Insertion
+        print(io, pos, content.seq)
+    else
+        print(io, pos, content.x)
+    end
+end
+
+function Base.in(v::Variation, var::Variant)
+    if v.ref != var.ref
+        error("References must be equal")
+    end
+    return any(v.edit == edit for edit in var.edits)
+end
+
+function translate(var::Variation{S,T}, aln::PairwiseAlignment{S,S}) where {S,T}
+    kind = var.edit.x
+    pos = var.edit.pos
+    seq, ref = aln.seq, aln.b
+
+    # Special case: Insertions may have a pos of 0, which cannot be mapped to
+    # the seq using ref2seq
+    if iszero(pos)
+        (s, r), _ = iterate(aln)
+        (isgap(s) | isgap(r)) && return Inapplicable()
+        return Variation{S,T}(seq, Edit{S,T}(Insertion(var.edit.x), 0))
+    end
+
+    (seqpos, op) = BA.ref2seq(aln, pos)
+    if kind isa Substitution
+        # If it's a substitution, return nothing if it maps to a deleted
+        # position, or substitutes to same base.
+        op in (BA.OP_MATCH, BA.OP_SEQ_MATCH, BA.OP_SEQ_MISMATCH) || return nothing
+        seq[seqpos] == kind.x && return nothing
+        edit = Edit{S,T}(kind, seqpos)
+        return Variation{S,T}(seq, edit, Unsafe())
+    elseif kind isa Deletion
+        # If it's a deletion, return nothing if the deleted part is already missing
+        # from the new reference.
+        (stop, op2) = BA.ref2seq(aln, pos + length(kind) - 1)
+        start = seqpos + op == BA.OP_DELETE
+        start < stop && return nothing
+        edit = Edit{S,T}(Deletion(stop - start + 1), start)
+        return Variation{S,T}(seq, edit, Unsafe())
+    else
+        # If it maps directly to a symbol, just insert
+        if op in (BA.OP_MATCH, BA.OP_SEQ_MATCH, BA.OP_SEQ_MISMATCH)
+            # This happens if there is already an insertion at the position
+            if pos != lastindex(ref) && first(ref2seq(aln, pos + 1)) != seqpos + 1
+                return Inapplicable()
+            else
+                edit = Edit{S,T}(Insertion(var.edit.x), seqpos)
+                return Variation{S,T}(seq, edit, Unsafe())
+            end
+            # Alternatively, it can map to a deletion. In that case, it become really
+            # tricky to talk about the "same" insertion.
+        else
+            return Inapplicable()
+        end
+    end
+end
+
+function variations(v::Variant{S,T}) where {S,T}
+    vs = Vector{Variation{S,T}}(undef, length(edits(v)))
+    for (i, e) in enumerate(edits(v))
+        vs[i] = Variation{S,T}(reference(v), e)
+    end
+    return vs
+end
+
+function refbases(v::Variation)
+    return _refbases(mutation(v), reference(v), leftposition(v))
+end
+
+function altbases(v::Variation)
+    return _altbases(mutation(v), reference(v), leftposition(v))
+end