1. In pea plants, yellow peas are dominant to green peas and purple flowers are dominant to white flowers. For each of the following parental crosses, give the predicted phenotypic and genotypic ratios of the F1 generation. Make punnet squares if necessary. 1. (heterozygous purple-flowered) x (heterozygous purple-flowered) 2. (true breeding white-flowered, yellow pea) x (true breeding purple-flowered, green pea) 3. (heterozygous purple-flowered, yellow pea) x (heterozygous purple-flowered, yellow pea) 2. You have a purple-flowered pea plant. You do not know its genotype. Diagram the test-cross you would conduct to determine the plant’s genotype and what results you would expect if the plant was heterozygous and if the plant was homozygous
1. In pea plants, yellow peas are dominant to green peas and purple flowers are dominant to
white flowers. For each of the following parental crosses, give the predicted phenotypic and
genotypic ratios of the F1 generation. Make punnet squares if necessary.
1. (heterozygous purple-flowered) x (heterozygous purple-flowered)
2. (true breeding white-flowered, yellow pea) x (true breeding purple-flowered, green
pea)
3. (heterozygous purple-flowered, yellow pea) x (heterozygous purple-flowered, yellow
pea)
2. You have a purple-flowered pea plant. You do not know its genotype. Diagram the test-cross
you would conduct to determine the plant’s genotype and what results you would expect if
the plant was heterozygous and if the plant was homozygous
3. You are studying five traits in Pentids, an amazonian flying beetle. You have identified each
trait as belonging to separate alleles located on separate chromosomes and have categorized
those alleles as A,B,C,D, and E, respectively. After years of controlled breeding experiments,
you have developed your Pentid lines to the point where you can control their genotypes with
certainty. You perform the following cross:
P: (AaBbCcDdEe) x (AAbbCCDdEe)Predict the probability of recovering offspring of each of the following genotypes from
this parental cross. You will definitely need to use a punnet square!
i. AaBbCcDdEe
ii. AAbbCCDDee
iii. AaBbCCDdEe
iv. AaBbccDdee
4. In cattle, roan coat color is an example of an autosomal, co-dominant phenotype. Roan (CrC
w)
cattle are produced from the mating of a white (CwC
w) cow to a red cow (CrC
r
). Predict the
phenotypic and genotypic frequencies of offspring from each of the following crosses:
1. Roan x White 3. Red x White
2. Roan x Red 4. Roan x Roan
5. Red-Green colour blindness is inherited as an X-linked recessive trait in humans. A woman, who’s
mother had red-green colour blindness marries a colour blind man. What are the chances that their
child will be:
1. a colour-blind male? 4. a normal male?
2. a colour blind female? 5. a normal female?
5. The couple has a colour blind male child. What are the chances that their next
child will be a normal female?
6. You have conducted exhaustive experiments studying the inheritance of four genes (A,B,C and
D) that are all on chromosome 3 in Drosophila melanogaster. You have recorded the following
frequencies of recombination in offspring for each of the genes:a b 20
a c 28
a d 5
b c 10
b d 15
c d 24
1. What is the order of the genes on the chromosome?
2. Why is the distance between genes a and c as shown in the data smaller than the
distance that is indicated by summing the smaller distances?
7. In guinea pigs, black hair colour (B) is dominant and brown hair colour (b) is recessive. Long hair (L)
is dominant and short hair (l) is recessive. Answer the following questions:
(a) Diagram the cross: BbLl x BbLL
(b) What are the
(c) What are the genotypes and phenotypes of the F1 generation?
8. About 70% of people get a bitter taste from the chemical phenyl thiocarbamide (PTC), while the
other 30% do not. The ability to taste this chemical (T) is a dominant characteristic, while taste-
blindness to it is recessive (t). Tongue-rolling ability is dominant (R), while the inability to roll the
tongue is recessive (r). A tongue-rolling woman who is taste-blind for PTC has a father who could not
roll his tongue but could taste the PTC chemical. She marries a man who can taste PTC but cannot roll
his tongue. His mother was taste-blind to the chemical. Show the possible children this couple could produced
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