Question 1

In 1940,two researchers named Weiner and Landsteiner discovered that about 85 percent of the human population sampled possessed a blood cell protein that had been previously detected in Rhesus monkeys.This blood type was labeled Rh positive,and Rh⁺ was found to be dominant over the absence of the blood factor (Rh^-).Under normal Mendelian inheritance,which of the following statements is FALSE?

Accepted Answer

Two Rh^- parents cannot have an Rh⁺ child because they both lack the Rh factor, meaning they can only pass on Rh^- alleles.

Question 2

If a woman is a carrier for the colorblind recessive allele and her husband is normal,what are their chances that their son will be color blind?

Accepted Answer

The son has a 50% chance of being colorblind because he inherits one X chromosome from his mother, who is a carrier, and one Y chromosome from his father. If he inherits the X chromosome carrying the colorblind allele, he will be colorblind.

Question 3

If a human who is a tongue roller (T)and has unattached ear lobes (E)marries a person who cannot roll their tongue and has attached earlobes,could they produce an offspring that was also a non-tongue-roller with attached earlobes? What would be the genotype of the first parent? The second parent?

Accepted Answer

The first parent must be heterozygous (TtEe) to potentially produce an offspring with the recessive traits (ttee) when crossed with the second parent (ttee).

Question 4

The particulate theory of inheritance

Accepted Answer

The answer of The particulate theory of inheritance
...

Question 5

Lethal genes (genes that result in the failure to develop a vital organ or metabolic pathway)are nearly always recessive.Animal breeders who discover a unique trait and selectively breed to increase the occurrence of that trait often encounter a noticeable increase in lethal genes.Why?

Accepted Answer

Inbreeding increases the likelihood that two recessive alleles, including lethal ones, will be inherited from both parents, leading to their expression.

Question 6

The ability to roll the edges of the tongue upward in a U-shape is considered to be an inherited trait.The standard assumption is that tongue-rolling is a dominant allele at a single gene locus.Which of the following would cast doubt on this assumption? Select all that apply.

Accepted Answer

The answer of The ability to roll the edges of...

Question 7

Unattached earlobes (EE or Ee)are described in the textbook as dominant over attached earlobes (ee).A couple both have unattached earlobes.Both notice that one of their parents on both sides has attached earlobes (ee).Therefore,they correctly assume that they are carriers for attached earlobes (Ee).The couple proceeds to have four children.

Accepted Answer

The couple, both being heterozygous (Ee), can have children with genotypes EE, Ee, or ee. The probability for each child is independent, so various combinations are possible, including all heterozygous, some homozygous dominant, or some homozygous recessive.

Question 8

The reason why some individuals who inherit polydactyly (having an extra digit on the hand or feet)do not express the trait is due to

Accepted Answer

Incomplete penetrance occurs when not all individuals with a mutant genotype show the mutant phenotype, explaining why some individuals with the gene for polydactyly do not express the trait.

Question 9

Computer simulations are sometimes used to demonstrate the outcome of monohybrid fruit fly crosses,where a student can run generation after generation of fruit flies with 100 offspring produced each generation,half male and half female,and a 3-to-1 phenotype ratio (or 75 to 25)in the F₁ generation.Compared with real genetics results,

Accepted Answer

In real genetics, exact numbers like 100 offspring, a perfect male-to-female ratio, and a precise 3-to-1 phenotype ratio are uncommon due to natural variations and environmental factors.

Question 10

An individual with blood type A marries an individual with blood type B.
A.What blood types could their offspring exhibit?
B.Provide the possible genotypes of parents and offspring produced.
C.What pattern of inheritance is this?

Accepted Answer

The answer of An individual with blood type A marries...

Question 11

In pea plants,the gene for round seeds (R)is dominant,and wrinkled seeds (r)is recessive.The endosperm of the pea is also either starchy,a dominant gene (S),or waxy (s).What can be said of a fully heterozygous,dihybrid cross?

Accepted Answer

In a fully heterozygous dihybrid cross (RrSs x RrSs), all combinations of alleles are possible, including homozygous dominant, homozygous recessive, and mixed homozygous/heterozygous combinations.

Question 12

If two parents have blood genotypes I^Ai and I^Bi,which of the following blood genotypes are possible in their children?

Accepted Answer

The possible genotypes for the children are I^Ai, I^Bi, I^AI^B, and ii, resulting from the combination of alleles from both parents.

Question 13

If the probability of event A is 3/4 and the probability of event B is 1/4,then the probability of both A and B occurring at the same time is

Accepted Answer

Since events A and B are independent, the probability of both occurring at the same time is found by multiplying their individual probabilities:

P(A and B) = P(A) x P(B) = (3/4) x (1/4) = 3/16

Question 14

Since each child of two heterozygous parents has a 50% chance of receiving a recessive trait from each parent,

Accepted Answer

Each child of two heterozygous parents has an independent 1/4 chance of being phenotypically recessive, regardless of the phenotype of any previous children.

Question 15

In a Punnett square,

Accepted Answer

A Punnett square is a diagram used to predict the genotypes of offspring from a particular cross or breeding experiment. It includes all possible types of sperm and eggs lined up either horizontally or vertically, and the results show the expected genotypes of the offspring.

Question 16

In what kind of classic Mendelian cross would you expect to find a ratio of 9:3:3:1 among the F₂ offspring?

Accepted Answer

A dihybrid cross is a cross between two individuals that are heterozygous for two different genes. The expected ratio of offspring in an F2 dihybrid cross is 9:3:3:1.

Question 17

As many as 60% of people in malaria-infected regions of Africa have the sickle-cell allele,but only about 10% of the U.S.population of African ancestry carries the allele.Malaria remains a major disease in central Africa but has not been a serious problem in the U.S.for many generations.What is/are the reason(s)for the difference in the percentages and what is a reasonable statement about future percentages?

Accepted Answer

The presence of malaria in Africa provides a selective advantage for the sickle-cell trait, maintaining its high frequency. In the U.S., the lack of malaria leads to negative selection against the allele. Immigration patterns also affect allele frequencies. All choices provide reasonable explanations for the observed differences and future trends.

Question 18

If individuals exhibiting a dominant phenotype are crossed and produce only offspring with the dominant phenotype,which of the following could be the genotype of the parents?

Accepted Answer

The answer of If individuals exhibiting a dominant phenotype are...

Question 19

Haiti is settled by peoples of both African and European ancestry.A young couple,both with mixed ancestry,marry and have several children.The children,who all have equal exposure to sunlight,vary widely in the amount of skin melanin.One child is lighter than both parents,and one is darker.The simple explanation for this is

Accepted Answer

Polygenic inheritance involves multiple genes contributing to a single trait, such as skin color, resulting in a wide range of phenotypes.

Question 20

A testcross involves an individual with the dominant phenotype but unknown genotype being crossed with an individual that has a(n)________ genotype.

Accepted Answer

A testcross is used to determine the genotype of an individual with a dominant phenotype by crossing it with an individual that is homozygous recessive.

Quiz 11: Mendelian Patterns of Inheritance

If a woman is a carrier for the colorblind recessive allele and her husband is normal,what are their chances that their son will be color blind?

If a human who is a tongue roller (T) and has unattached ear lobes (E) marries a person who cannot roll their tongue and has attached earlobes,could they produce an offspring that was also a non-tongue-roller with attached earlobes? What would be the genotype of the first parent? The second parent?

The particulate theory of inheritance

Lethal genes (genes that result in the failure to develop a vital organ or metabolic pathway) are nearly always recessive.Animal breeders who discover a unique trait and selectively breed to increase the occurrence of that trait often encounter a noticeable increase in lethal genes.Why?

The ability to roll the edges of the tongue upward in a U-shape is considered to be an inherited trait.The standard assumption is that tongue-rolling is a dominant allele at a single gene locus.Which of the following would cast doubt on this assumption? Select all that apply.

The reason why some individuals who inherit polydactyly (having an extra digit on the hand or feet) do not express the trait is due to

An individual with blood type A marries an individual with blood type B. A.What blood types could their offspring exhibit? B.Provide the possible genotypes of parents and offspring produced. C.What pattern of inheritance is this?

In pea plants,the gene for round seeds (R) is dominant,and wrinkled seeds (r) is recessive.The endosperm of the pea is also either starchy,a dominant gene (S) ,or waxy (s) .What can be said of a fully heterozygous,dihybrid cross?

If two parents have blood genotypes I^Ai and I^Bi,which of the following blood genotypes are possible in their children?

If the probability of event A is 3/4 and the probability of event B is 1/4,then the probability of both A and B occurring at the same time is

Since each child of two heterozygous parents has a 50% chance of receiving a recessive trait from each parent,

In a Punnett square,

In what kind of classic Mendelian cross would you expect to find a ratio of 9:3:3:1 among the F₂ offspring?

If individuals exhibiting a dominant phenotype are crossed and produce only offspring with the dominant phenotype,which of the following could be the genotype of the parents?

A testcross involves an individual with the dominant phenotype but unknown genotype being crossed with an individual that has a(n) ________ genotype.

Quiz 11: Mendelian Patterns of Inheritance

If a woman is a carrier for the colorblind recessive allele and her husband is normal,what are their chances that their son will be color blind?

If a human who is a tongue roller (T) and has unattached ear lobes (E) marries a person who cannot roll their tongue and has attached earlobes,could they produce an offspring that was also a non-tongue-roller with attached earlobes? What would be the genotype of the first parent? The second parent?

The particulate theory of inheritance

Lethal genes (genes that result in the failure to develop a vital organ or metabolic pathway) are nearly always recessive.Animal breeders who discover a unique trait and selectively breed to increase the occurrence of that trait often encounter a noticeable increase in lethal genes.Why?

The ability to roll the edges of the tongue upward in a U-shape is considered to be an inherited trait.The standard assumption is that tongue-rolling is a dominant allele at a single gene locus.Which of the following would cast doubt on this assumption? Select all that apply.

The reason why some individuals who inherit polydactyly (having an extra digit on the hand or feet) do not express the trait is due to

An individual with blood type A marries an individual with blood type B. A.What blood types could their offspring exhibit? B.Provide the possible genotypes of parents and offspring produced. C.What pattern of inheritance is this?

In pea plants,the gene for round seeds (R) is dominant,and wrinkled seeds (r) is recessive.The endosperm of the pea is also either starchy,a dominant gene (S) ,or waxy (s) .What can be said of a fully heterozygous,dihybrid cross?

If two parents have blood genotypes IAi and IBi,which of the following blood genotypes are possible in their children?

If the probability of event A is 3/4 and the probability of event B is 1/4,then the probability of both A and B occurring at the same time is

Since each child of two heterozygous parents has a 50% chance of receiving a recessive trait from each parent,

In a Punnett square,

In what kind of classic Mendelian cross would you expect to find a ratio of 9:3:3:1 among the F2 offspring?

If individuals exhibiting a dominant phenotype are crossed and produce only offspring with the dominant phenotype,which of the following could be the genotype of the parents?

A testcross involves an individual with the dominant phenotype but unknown genotype being crossed with an individual that has a(n) ________ genotype.

If two parents have blood genotypes I^Ai and I^Bi,which of the following blood genotypes are possible in their children?

In what kind of classic Mendelian cross would you expect to find a ratio of 9:3:3:1 among the F₂ offspring?