Download Practice Crosses

Name ______________________________ Date _________________ Period _______
Practice Crosses
1) Pansies are an annual flowering plant popular in many gardens in England. Purple flowers (P) are
dominant over yellow flowers (p) and hairy (hirsute) stems and leaves (H) are dominant over smooth stems
and leaves (e). Perform a dihybrid cross between a heterozygous purple, smooth stemmed pansy and a
heterozygous purple, hairy pansy.
How many Pansies have:
Purple flowers and hairy stems
Purple flowers and smooth stems
Yellow flowers and hairy stems
Yellow flowers and smooth stems
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2) In cats short hair (H) is dominant over long hair (h), and a straight tail (T) is not dominant over a kinked tail
(K), but rather the presence of a straight tail gene and a kinked tail gene results in a bent tail. Perform a
dihybrid cross between a heterozygous short haired kinked tailed cat and a long haired, bent tailed cat.
How many cats have:
Short hair and kinked tail
Short hair and straight tail
Short hair and bent tail
Long hair and kinked tail
Long hair and straight tail
Long hair and bent tail
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3) Zebras can have a condition where their stripes run horizontally instead of vertically. This is a sex-linked
condition. They also have a condition where their ears twitch excessively. This is not sex-linked, but the
excessive ear twitching is recessive to normal ears. Perform a dihybrid cross between a vertically striped male
zebra with heterozygous normal ears and a female that has twitchy ears and is heterozygous for vertical
stripes.
How many zebras have:
Vertical stripes and normal ears
Vertical stripes and twitchy ears
Horizontal stripes and normal ears
Horizontal stripes and twitchy ears
Males with horizontal stripes
Females with horizontal stripes
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4) Attached ear lobes are dominant to free ear lobes. Hair is dominant to baldness, and is a sex-linked trait.
The size of the jaw can range from large, lantern jawed (homozygous) to medium (heterozygous) to small
(homozygous).
Lloyd is lantern jawed, hairy, and has attached ear lobes (heterozygous). Lana has a small jaw, free ear lobes,
with lots of hair (heterozygous). Determine all of the different phenotype combinations their children could
have along with the probabilities for each.
Possibilities:
Male, hairy, lantern jawed, attached ear lobe
Male, hairy, lantern jawed, free ear lobe
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