1. In rabbits, mono-colored fur (F) is dominant over spotted fur (f), and straight
ears (S) is dominant over floppy (s).
2. Your son is interested in obtaining a spotted floppy-eared rabbit for
entry into the fair. You have a male FfSs and a female ffss, and female rabbits
often produce about eight babies per litter. Figure out the ratio of poffspring
for each phenotype you can expect from crossing these rabbits, so you can
decide if it is likely that your son can enter the fair with a spotted floppy-eared
rabbit.
3. The ruffed chicken has an under-chin wattle. A smooth wattle (S) is
dominant over a wrinkled wattle (s). A red wattle (HR) is
incompletely dominant with a white wattle (HW) so that an individual
with HRHW will have a pink wattle.
4. In turkeys, bronze body color (B) is dominant over red (b). Normal feathers
(N) are dominant over hairy feathers (n). A bronze male turkey is mated to a
bronze female, and some of the poults (baby turkeys) produced by this cross
are red. What are the genotypes of the male and female parents and the red
poults?
5. Some of the poults from the cross described in #1 above are bronze.
What proportion of the poults would you expect to have the BB genotype?
What proportion would have the Bb genotype? What proportion would
have the bb genotype?
6. If you were to cross a Bbnn turkey with a bbNn turkey,
what proportion of the offspring will have red, normal feathers? What
proportion will have bronze hairy feathers? red, hairy feathers? bronze,
normal feathers?
7. A breeder of hamsters crosses a golden hamster with a black hamster.
All the baby hamsters are golden. Which trait is dominant and which is
recessive? What are the genotypes of the parents? What are the genotypes
of the babies?
8. The breeder takes one of the babies, raises it to maturity, and then
mates it to a black hamster. Use a Punnett square to predict the results
of this crossbreeding. Predict the genotype(s) and phenotype(s) of
the offspring, and the expected ratios.
9. In hamsters, long fur is recessive and short fur is dominant. Suppose
the breeder takes a hamster that is heterozygous for both golden fur
and short fur, and mates it to a hamster with long black fur. Use a
Punnett square to prediict the results of this crossbreeding. Predict
the genotype(s) and phenotype(s) of the offspring, and the expected ratios.
10. Humans have four possible blood types (A, B, AB, and O) and these blood types are
controlled by three alleles (IA, IB, i). The
IA and IB alleles are codominant (they share
expression, thus we have an AB blood type), but they are both dominant over the
i allele.
Homozygous recessive?
Heterozygous?
What are the expected genotypes and their ratio?
Phenotype ratio?
Monocolored fur and floppy ears: _____________
Spotted fur and straight ears: _____________
Spotted fur and floppy ears: _____________
Blood Type B:
Blood Type AB:
Blood Type O:
11. Red-green color blindness, in humans, is a sex-linked trait controlled by alleles on the X chromosome. Normal color vision (X+) is dominant to colorblindness (Xc). [NOTE: You could write this as XC for the normal allele and Xc for the recessive colorblind allele. Unfortunately, capital C and lowercase c are hard to tell apart as superscripts, especially in type. Use X+ -- "X-plus" -- for the normal allele.]
12. Budgies (Melanopsittacus undulatus) are attractive birds that come in many colors. Budgies may produce either or both of two types of pigment in their feathers: a blue pigment and a yellow pigment. Whether or not each pigment is produced is governed by one gene with two alleles. Blue pigment (B) is dominant to no blue pigment (b), and yellow pigment (Y) is dominant to no yellow pigment (y). A budgie that produces neither blue nor yellow pigment in its feathers looks white. A budgie that produces both blue and yellow pigment in its feathers looks green.