GENETICS PROBLEMS
- Albinism occurs commonly in animals, and it is always recessive to the normal. Six
brown and five albino mice were born to parents who were brown and albino,
respectively. What is the genotype of the brown parent?
- In tomatoes, red fruit color is dependent on a dominant gene, R; yellow is dependent
upon its recessive allele r; tallness is due to a dominant gene, D; dwarfness to its
recessive allele, d. The Golden Beauty variety has yellow fruit and is tall. The Dwarf
Giant is dwarf with red fruit. If a homozygous Golden Beauty was cross-pollinated
with a homozygous Dwarf Giant, what would you expect in the F2 generation?
- In shorthorn cattle, a cross between a white cow and red bull gives an offspring of an
intermediate type known as roan. If two roan cattle were bred, what would you expect?
- In cats, yellow is due to a gene, B, and black to its allele, b. The heterozygous
condition, Bb, results in tortoise-shell. The genes B and b are sex-linked. What kinds
of offspring would result from a cross between a yellow male and a black female?
- If a person of blood group 0 marries a person of blood group AB, what blood groups
are possible among their children?
- In cocker spaniels, black is dominant to red. Two black cocker spaniels have 9 puppies;
5 black and 4 red. What is the genotype of each parent?
- A brown-eyed man whose mother was color-blind and whose father had blue eyes is
engaged to marry a woman whose color-blind mother had blue eyes and whose normal
visioned father had blue eyes. If they marry, and have a family, what are the possible
offspring?
- How many human sperm will result from fifty primary spermatocytes?
- In dogs, wire hair is due to a dominant gene, smooth hair to its recessive allele. Two
wire-haired dogs produce a male pup which is wire-haired. To discover quickly
whether he carries the gene for smooth hair, he should be mated to what kind of
female?
- If two parents have blood group AB could any of their children act as blood donors for
their parents?