BIOL 1500 Chapter : GeneticsProblems_Answers.pdf
BIOL 1010 – Genetics practise problems – answers
1
1. In rabbits, coat colour is a genetically determined characteristic. Some black females always
produce black progeny, while other black females produce black progeny and white progeny.
Explain how these outcomes occur.
In this example, the allele for black coat colour is completely dominant over the
allele for white coat colour.
E.g. Black = B, white = b.
Females who produce only black progeny are likely to have genotype BB, while
those who produce black progeny as well as white progeny would have genotype
Bb.
2. How many different types of gametes can be formed by individuals of the following genotypes?
What are the possible gamete genotypes?
a) AaBb - 4 possible combinations:
1/2 A x 1/2 B = 1/4 AB
1/2 a x 1/2 B = 1/4 aB
1/2 A x 1/2 b = 1/4 Ab
1/2 a x 1/2 b = 1/4 ab
b) AaBbCc - 8 possible combinations:
1/2 A x 1/2 B x 1/2 C = 1/8 ABC
1/2 a x 1/2 B x 1/2 C = 1/8 aBC
1/2 A x 1/2 b x 1/2 C = 1/8 AbC
1/2 a x 1/2 b x 1/2 C = 1/8 abC
1/2 A x 1/2 B x 1/2 c = 1/8 ABc
1/2 a x 1/2 B x 1/2 c = 1/8 aBc
1/2 A x 1/2 b x 1/2 c = 1/8 Abc
1/2 a x 1/2 b x 1/2 c = 1/8 abc
c) AaBBcc - 2 possible combinations:
1/2 A x 1 B x 1 c = 1/2 ABc
1/2 a x 1 B x 1 c = 1/2 aBc
d) AaBbcc - 4 possible combinations:
1/2 A x 1/2 B x 1 c = 1/4 ABc
1/2 a x 1/2 B x 1 c = 1/4 aBc
1/2 A x 1/2 b x 1 c = 1/4 Abc
1/2 a x 1/2 b x 1 c = 1/4 abc
Document Summary
Biol 1010 genetics practise problems answers: in rabbits, coat colour is a genetically determined characteristic. Some black females always produce black progeny, while other black females produce black progeny and white progeny. In this example, the allele for black coat colour is completely dominant over the allele for white coat colour. Females who produce only black progeny are likely to have genotype bb, while those who produce black progeny as well as white progeny would have genotype. What are the possible gamete genotypes: aabb - 4 possible combinations: 1/2 a x 1/2 b = 1/4 ab. 1/2 a x 1/2 b = 1/4 ab: aabbcc - 8 possible combinations: 1/2 a x 1/2 b x 1/2 c = 1/8 abc. 1/2 a x 1/2 b x 1/2 c = 1/8 abc: aabbcc - 2 possible combinations: 1/2 a x 1 b x 1 c = 1/2 abc.