Exam 23: Patterns of Gene Inheritance

You have two true-breeding rose bushes, one with red flowers and one with white flowers. A cross between these two roses yields a rose bush with two-color flowers. Each flower is both red and white. This is an example of

Which of the following crosses will yield only homozygous recessive offspring?

In the following pedigree, the inherited condition is due to an autosomal dominant allele.

If one parent has type B blood and the other has type AB, what type might the child have?

In guinea pigs, B = black, b = brown, S = short hair, s = long hair. A black, short-haired animal who is homozygous for both traits, reproduces with a brown, long-haired animal. What is the expected phenotypic ratio of the offspring?

In horses, black coat (B) is dominant over brown coat (b), and being a trotter (T) is dominant over being a pacer (t). A black horse who is a pacer is crossed with a brown horse who is a trotter. The offspring is a brown pacer. What is the genotype of the brown trotter parent?

In 1940, two researchers named Weiner and Landsteiner discovered that about 85% of the human population sampled possessed a blood cell protein called the Rh factor. The presence of Rh factor was labeled Rh positive (Rh⁺) and was found to be dominant over the absence of the blood factor (Rh^-). Rh factor is inherited in a typical Mendelian pattern. Based on this information, one could predict that two Rh⁺ parents could never have an Rh^- child.

The leaves of a maple tree vary in size depending on the location of the leaves on the tree. Those growing at the outer region of the tree tend to be smaller than those growing closer to the trunk of the tree. This allows leaves that are growing in the shade to have a larger surface area. This is an example of

In four o'clock flowers, R = red, r = white, and Rr = pink. If two hybrids are crossed, what are the chances that an offspring will have pink flowers?

When pairs of factors separate independently of other pairs of factors, this is known as

Both parents are heterozygous for Tay-Sachs disease (an autosomal recessive disorder). Three children in a row were born with Tay-Sachs disease. What is the chance that a fourth child will have Tay-Sachs disease?

The alternate forms of a gene for the same trait are known as

An individual with a dominant phenotype is crossed with an individual with a recessive phenotype. Five out of nine offspring show the dominant phenotype. What is the genotype of the dominant parent?

Which genetic disorder is associated with an irregular shape of the red blood cells?

Consider skin color is regulated by three genes: A, B, and C. All recessive alleles would be 0 or white on the color scale. All dominant alleles would be 6 or black on the color scale. What color is a person with AAbbCc genotype?

Tay-Sachs is a recessive genetic disease in humans. If one parent is homozygous normal and the other is a carrier (heterozygous), what are the chances that their child will have this disease?

In humans, brown eyes (B) are a simple dominant trait over blue eyes (b). What is the genotype of a brown-eyed woman who has a blue-eyed child?

When investigators try to determine what percentage of various human traits is due to nature (inheritance) and what percentage is due to nurture (the environment), scientists often examine

Which of the following crosses will yield four phenotypes in the 1:1:1:1 ratio?

When two or more sets of alleles affect the same trait, it is termed