In dihybridism without epistasis
heterozygous parental individuals cross
in F2 4 phenotypical appear.
The proportion is double dominant to
3 for the first pair,
for the second to recessive for the
first , dominant for the second 1
double recessive (9:3:3:1).

that the epistatic gene
the second pair and the recessive
genotype of hypostatic gene means
lacking the characteristic, in the
generation of the dominant the
following phenotypical forms
emerge: 13 dominant for second
pair or recessive the first, i.e., the
not manifest, 3
dominant the first pair, recessive
the second, i.e., the
manifests. The phenotypical proportion
be13:3. In the recessive
in F2 the phenotypical
that would emerge are: double
dominant (the characteristic ),
7 recessive for the pair or recessive
for second, i.e., the characteristic
not manifest. So the
proportion would be 9:7.

examples show how epistasis
phenotypical forms and
proportions, the normal 9:3:3:1 in
to 13:3 in dominant or to
9:7 in epistasis (note that
some have even disappeared).
(If recessive genotype of the
gene is active, not
meaning that the dominant does
not manifest, the of
phenotypical forms in changes.)