Due day of test: _______________
Name: ______________
Genetics Review –
Failure to complete will result of deduction of 6 points on your test grade!
Vocabulary  this unit is all about knowing your vocabulary to solve problems!
Gene
Allele
Dominant
Recessive
Genotype
Phenotype
Co-dominance
Incomplete Dominance

In humans, brown eyes (B) are dominant over blue (b). A brown-eyed man marries a blue-eyed
woman and they have three children, two of whom are brown-eyed and one of whom is blueeyed.
1. Draw the Punnett square that illustrates this marriage.
2. What is the man’s genotype? _____________________
3. What are the genotypes of the children? ____________

In cats fur color is a co-dominant gene. A cross between a black cat & a tan cat produces a
tabby pattern (black & tan fur together).
4. What percent of kittens would have tan fur if a tabby cat is crossed with a black cat?

In cattle, red (r) is incompletely dominant over white (w) hides. Roan is the
name of the color that results from incomplete dominance.
5. What are the possible results if a white male mates with a roan female?
____________________________________
I
II
1
2
1
2
4
5
3
= Huntington’s
Disease
6
7
8
III
1
2
3
4
5
6a. Which members of the family above are afflicted with Huntington’s Disease? ________________________________
b.How are individuals III-2 and II-4 related? ________________________ I-2 and III-5? _________________________
Due day of test: _______________
Name: ______________
Assignment Due: _________
CODOMINANT TRAITS
In humans, wavy hair (CS) results by the co-dominant situation of curly hair (C) and straight hair (S).
What are the possible results if a curly-haired man and wavy-haired woman have
children? (phenotypic percentages)
In crocus flowers, white (W) and purple (P) colors are co-dominant, and result in a purple and white
striped flower when both genes are present.
What are the possible results from the cross-pollination of a striped crocus with a white crocus? (phenotypic
percentages)
INCOMPLETE DOMINANCE
The feather color of a blah-blah bird is an incomplete dominant gene. A cross between a blue blah-blah
bird (I made this bird up) & a white blah-blah bird produces offspring that are silver.
What are the genotypes of the parent blahblah birds in the original cross?
What is the genotype of the silver offspring? _________
What would be the phenotypic ratios of offspring produced by two silver blahblah birds?
____________________________________