Exam 19: Introduction to Genetics

Garden Peas In garden peas, one pair of alleles controls the height of the plant and a second pair of alleles controls flower color. The allele for tall ( D ) is dominant to the allele for dwarf ( d ), and the allele for purple ( P ) is dominant to the allele for white ( p ). Use this information to answer the following question(s). In the garden peas example above, a tall plant with white flowers crossed with a dwarf plant with purple flowers produces all tall offspring with purple flowers. What is the genotype of the parents?

When considering non-related traits, the fact that they may be inherited individually without any effect on one another is known as

Assume red plants crossed with white plants give rise to pink plants. Explain how to eliminate red plants if you start with two pink plants.

What fraction of the time will the cross of Aa Bb Cc with Aa Bb Cc produce an offspring of genotype Aa bb CC ?

A breeder of cattle has a herd of white cows and a roan bull. Hair color in this breed is controlled by an incompletely dominant gene. The two homozygous forms are either red or white, and the heterozygous is roan. (a) What color of calves are expected and in what proportions? (b) Outline a procedure to develop an all-red herd.

Garden Peas In garden peas, one pair of alleles controls the height of the plant and a second pair of alleles controls flower color. The allele for tall ( D ) is dominant to the allele for dwarf ( d ), and the allele for purple ( P ) is dominant to the allele for white ( p ). Use this information to answer the following question(s). In the garden peas example above, a tall plant with white flowers crossed with a dwarf plant with purple flowers produces 1/4 tall purple flowers, 1/4 tall white flowers, 1/4 dwarf purple flowers, and 1/4 dwarf white flowers. What is the genotype of the parents?

In a certain plant, when individuals with blue flowers are crossed with individuals with blue flowers, only blue flowers are produced. Plants with red flowers crossed with plants with red flowers sometimes produce only red flowers, while other times they produce either red or blue flowers. When plants with red flowers are crossed with plants with blue flowers, sometimes only red flowers are produced; other times either red or blue flowers are produced. Which gene is dominant?

Garden Peas In garden peas, one pair of alleles controls the height of the plant and a second pair of alleles controls flower color. The allele for tall ( D ) is dominant to the allele for dwarf ( d ), and the allele for purple ( P ) is dominant to the allele for white ( p ). Use this information to answer the following question(s). In the garden peas example above, a tall plant with purple flowers crossed with a tall plant with white flowers produces 3/8 tall purple flowers, 1/8 tall white flowers, 3/8 dwarf purple flowers, and 1/8 dwarf white flowers. What is the genotype of the parents?

If black fur color is controlled by a dominant allele ( B ) and brown by its recessive allele ( b ), give the genotypes of the parents and offspring of a cross of a black male with a brown female that produces 1/2 black offspring and 1/2 brown offspring.

If wire hair ( W ) is dominant to smooth hair ( w ) and you find a wire-haired puppy, how would you determine its genotype by a genetic breeding experiment? Give both the genotype and phenotype involved with the cross with the unknown.

The trait of having more than ten fingers or toes is called

Crosses between a yellow rat and a yellow rat always produce yellow. Crosses between a white rat and a white rat always produce white. The alleles affect the same aspect of coat color. The crosses of a white rat and a yellow rat produce cream. What happens if you cross two cream rats?

Selecting the Exception Four of the five answers listed below describe the gene makeup. Select the exception.

The ABO blood types have ____ different genotypes.

A gene that has three or more alleles is called a

If 2 spot ( S ) is dominant to 4 spot ( s ), give the genotypes for the parents in the following crosses: (a) 2 spot x 2 spot yields 2 spot and 4 spot (b) 2 spot x 4 spot yields only 2 spot (c) 2 spot x 4 spot yields 2 spot and 4 spot (d) 2 spot x 2 spot yields only 2 spot (e) 4 spot x 4 spot yields only 4 spot

When the first generation parents are homozygous for different alleles, a 3:1 phenotype ratio will most likely appear in which generation of offspring?

Pure-breeding yellow guinea pigs crossed with pure-breeding white ones produce only cream-colored offspring. This pattern indicates incomplete dominance. Rough hair is found to be dominant to smooth hair. Give the F ₁ and F ₂ genotypic and phenotypic ratios of a cross of a smooth, white guinea pig with a homozygous, rough, yellow guinea pig.

Selecting the Exception Four of the five answers listed below describe the heterozygous condition. Select the exception.

For monohybrid experiments, a testcross could result in which of the following ratios?