DiHvbrid Cross problems- used to illustrate the
Principle of Independent Assortment
Directions:
a.
Please provide ONLY phenotypic ratios for ALL
CTOSSCS
b.
L
YOU WILL NEED a lot of paper since EACH cRoss
is a 16-box Punnett Square!
In Cats, Black fur (B) is dominant to Orange (b) fur.
In addition, Long tails (L) are dominant to short (l)
tails
a.
b.
c.
II.
a.
b.
c.
Cross a Black, long tailed cat (homozygous-both) with a
Orange, short tail cat
Cross a Black (homozygous), short tail cat with a
Orange, short tail cat
Cross a Black, long tail cat (homozygous-both) with a
Orange, long tailed cat (heterozygous)
In Ducks, Brown feathers (B) are dominant to white
(b) feathers. In addition, Straight bills (T) are
dominant to curved (t) bills.
Cross a brown, straight bill duck (heterozygous-both)
with a brown (homozygous), curved bill duck
Cross a brown, straight bill duck (homozygous-both)
with a brown, straight bill duck (heterozygous-both)
Cross (2) ducks-brown, straight billed (heterozygousboth)