Chapter 3: Mol Gen

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene. Two parents with normal pigmentation have an albino child. What is the probability that their next child will be a wild type girl? A) 3/4 B) 3/8 C) 1/2 D) 0% E) 1/4

B) 3/8

Which phenotypic ratio is likely to occur in crosses of two completely dominant, independently segregating gene pairs when both parents are fully heterozygous? A) 2:4:6:8 B) 9:3:3:1 C) 3:2:3:1 D) 1:1:1:1 E) 3:1

B) 9:3:3:1

Which types of phenotypic ratios are likely to occur in crosses when dealing with two gene pairs for which all the genotypic combinations are of equal viability? A) 6:6:2 B) 9:3:3:1 C) 12:2:2 D) 2:3, 1:2 E) 1:2:1, 3:1

B) 9:3:3:1

To test Mendel's Law of Segregation, the experimenter needs ________. A) the ability to perform a test cross B) a minimum of two contrasting forms of a gene C) access to several generations of data D) a DNA sequencing apparatus E) at least 500 offspring to count

B) a minimum of two contrasting forms of a gene

Assuming no crossing over between the gene in question and the centromere, when do alleles segregate during meiosis? A) prophase I B) anaphase I C) anaphase II D) interphase E) prophase II

B) anaphase I

You have identified a plant in your garden with a new flower color. You want to determine if this phenotype is dominant or recessive. Which cross would tell you this? A) selfing the plant B) crossing the plant to one you know has the recessive trait C) crossing the plant to a plant of the same type of any color D) sequencing the DNA for the trait E) crossing the new plant to one you know has the dominant trait

B) crossing the plant to one you know has the recessive trait

Which of the following groups of scientists were influential around the year 1900 in setting the stage for our present understanding of transmission genetics? A) Darwin, Mendel, and Lamarck B) de Vries, Correns, Tschermak, Sutton, and Boveri C) Beadle, Tatum, and Lederberg D) Hippocrates, Aristotle, and Kölreuter E) Watson, Crick, Wilkins, and Franklin

B) de Vries, Correns, Tschermak, Sutton, and Boveri

Which of the following is true? A) Assume that a Chi-square test was conducted to test the goodness of fit to a 3:1 ratio and that a Chi-square value of 2.62 was obtained. The null hypothesis should be accepted. B) Assume that a Chi-square test was conducted to test the goodness of fit to a 9:3:3:1 ratio and a Chi-square value of 10.62 was obtained. The null hypothesis should be accepted. C) Assume that a Chi-square test provided a probability value of 0.02. The null hypothesis should be accepted. D) With the test of a 3:1 ratio, there are three degrees of freedom. E) The large the Chi-square value, the more likely your results are real.

A) Assume that a Chi-square test was conducted to test the goodness of fit to a 3:1 ratio and that a Chi-square value of 2.62 was obtained. The null hypothesis should be accepted.

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene. Two parents with normal pigmentation have an albino child. What is the probability that their next child will be albino? A) 1/16 B) 1/2 C) 1/3 D) 1/4 E) 3/4

A) 1/16

Dentinogenesis imperfecta is a rare, autosomal, dominantly inherited disease of the teeth that occurs in about one in 8000 people (Witkop 1957). The teeth are somewhat brown in color, and the crowns wear down rapidly. Assume that a male with dentinogenesis imperfecta and no family history of the disease marries a woman with normal teeth. What is the probability that their first child will be a girl with dentinogenesis imperfecta? A) 1/4 B) 1/2 C) 100% D) 1/8 E) 3/4

A) 1/4

Dentinogenesis imperfecta is a rare, autosomal, dominantly inherited disease of the teeth that occurs in about one in 8000 people (Witkop 1957). The teeth are somewhat brown in color, and the crowns wear down rapidly. Assume that a male with dentinogenesis imperfecta and no family history of the disease marries a woman with normal teeth. What is the probability that their first two children will have dentinogenesis imperfecta? A) 1/4 B) 1/8 C) 1/2 D) 100% E) 3/4

A) 1/4

Which types of phenotypic ratios are likely to occur in crosses when dealing with a single gene pair for which all the genotypic combinations are of equal viability? A) 1:2:1, 3:1 B) 2:3, 1:2 C) 9:3:3:1, 27:9:9:9:3:3:3:1 D) 1:4:6:4:1, 1:1:1:1 E) 12:3:1, 9:7

A) 1:2:1, 3:1

A recessive allele in dogs causes white spots. If two solid colored dogs are mated and produce a spotted offspring, what is the percentage chance their next puppy would be solid colored? A) 75% B) about 90% C) 25% D) about 66% E) 50%

A) 75%

In what ways is sample size related to statistical testing? A) By increasing sample size, one increases the reliability of the statistical test and decreases the likelihood of erroneous conclusions from chance fluctuations in the data. B) The larger the sample size is, the more likely you are to introduce errors into your data. C) By increasing sample size, one decreases the reliability of the statistical test and increases the likelihood of erroneous conclusions from chance fluctuations in the data. D) There is no correlation. E) By increasing sample size, one increases the reliability of the statistical test and increases the likelihood of erroneous conclusions from chance fluctuations in the data.

A) By increasing sample size, one increases the reliability of the statistical test and decreases the likelihood of erroneous conclusions from chance fluctuations in the data.

What is segregation? A) During gamete formation, allele pairs are separated to form haploid gametes. B) During gamete formation, segregating pairs of unit factors assort independently of each other. C) Chromosomes can swap information during meiosis. D) Fertilization is random. E) Genes lie on chromosomes.

A) During gamete formation, allele pairs are separated to form haploid gametes.

What is independent assortment? A) During gamete formation, segregating pairs of unit factors assort independently of each other. B) During gamete formation, allele pairs are separated to form haploid gametes. C) Genes lie on chromosomes. D) Fertilization is random. E) Chromosomes can swap information during meiosis.

A) During gamete formation, segregating pairs of unit factors assort independently of each other.

Name the single individual whose work in the mid-1800s contributed to our understanding of the particulate nature of inheritance as well as the basic genetic transmission patterns. With what organism did this person work? A) Gregor Mendel; Pisum sativum B) Calvin Bridges; Drosophila C) Boris Ephrussi; Ephestia D) George Beadle; Neurospora E) Thomas Hunt Morgan; Drosophila

A) Gregor Mendel; Pisum sativum

Two organisms, AABBCCDDEE and aabbccddee, are mated to produce an F1 that is self-fertilized. If the capital letters represent dominant, independently assorting alleles. How many different genotypes will occur in the F2? A) 25 B) 243 C) 64 D) 1024 E) 32

B) 243

Which types of phenotypic ratios are likely to occur in crosses when dealing with three gene pairs for which all the genotypic combinations are of equal viability? A) 1:2:1, 3:1 B) 27:9:9:9:3:3:3:1 C) 1:4:6:4:1, 1:1:1:1 D) 12:3:1, 9:7 E) 2:3, 1:2

B) 27:9:9:9:3:3:3:1

The phenotype of vestigial (short) wings (vg) in Drosophila melanogaster is caused by a recessive mutant gene that independently assorts with a recessive gene for hairy (h) body. Assume that a cross is made between a fly with normal wings and a hairy body and a fly with vestigial wings and normal body hair. The wild-type F1 flies were crossed among each other to produce 1024 offspring. Which phenotypes would you expect among the 1024 offspring, and how many of each phenotype would you expect? A) Phenotypes: wild, vestigial, hairy, and vestigial hairy; Numbers expected: wild (576), vestigial (192), hairy (192), and vestigial hairy (64). B) All vestigial hairy. C) Phenotypes: wild, vestigial, hairy, and vestigial hairy; Numbers expected: wild (192), vestigial (256), hairy (64), and vestigial hairy (192). D) Phenotypes: wild, vestigial, hairy, and vestigial hairy; Numbers expected: wild (256), vestigial (256), hairy (256), and vestigial hairy (256). E) All wild type.

A) Phenotypes: wild, vestigial, hairy, and vestigial hairy; Numbers expected: wild (576), vestigial (192), hairy (192), and vestigial hairy (64).

Assume that a black guinea pig crossed with an albino guinea pig produced 5 black offspring. When the albino was crossed with a second black guinea pig, 4 black and 3 albino offspring were produced. What genetic explanation would apply to these data? A) albino = recessive; black = dominant B) albino = dominant; black = incompletely dominant C) albino = dominant; black = recessive D) albino and black = codominant E) albino = recessive; black = recessive

A) albino = recessive; black = dominant

The number of possible gametes, each with different chromosome compositions, is 2n, where n equals ________. A) the haploid number B) the number of offspring C) the diploid number D) the number of alleles E) the number of genes

A) the haploid number

Dentinogenesis imperfecta is a rare, autosomal, dominantly inherited disease of the teeth that occurs in about one in 8000 people. The teeth are somewhat brown in color, and the crowns wear down rapidly. Assume that a male with dentinogenesis imperfecta and no family history of the disease marries a woman with normal teeth. What is the probability that their first child will have dentinogenesis imperfecta? A) 100% B) 1/2 C) 3/4 D) 1/8 E) 1/4

B) 1/2

Polydactyly is expressed when an individual has extra fingers and/or toes. Assume that a man with six fingers on each hand and six toes on each foot marries a woman with a normal number of digits. Having extra digits is caused by a dominant allele. The couple has a son with normal hands and feet, but the couple's second child has extra digits. What is the probability that their next child will have polydactyly? A) 1/8 B) 1/2 C) 1/32 D) 3/4 E) 7/16

B) 1/2

The autosomal (not X-linked) gene for brachydactyly, short fingers, is dominant to normal finger length. Assume that a female with brachydactyly in the heterozygous condition is married to a man with normal fingers. What is the probability that their first two children will have brachydactyly? A) 2/3 B) 1/4 C) 3/4 D) 1/8 E) 1/2

B) 1/4

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene (a). Two parents with normal pigmentation have an albino child. What is the probability that their next child will be an albino girl? A) 1/2 B) 1/8 C) 1/4 D) 3/4 E) 1/3

B) 1/8

Mendel's Law of Segregation is supported by a ________ testcross ratio. A) 3:2 B) 1:1 C) 5:2 D) 3:1 E) 2:1

B) 1:1

For which of the following questions would you use the sum law? A) determining the chance of having a tall plant with purple flowers B) determining the chance of pulling either a club or a heart from a deck of cards C) determining the chance of pulling an ace from a deck of cards D) determining the chance of having a baby girl E) determining the change of rolling a 5 on a ten-sided die

B) determining the chance of pulling either a club or a heart from a deck of cards

What meiotic process, relative to the number of chromosomes of a given species, accounts for a significant amount of genetic variation in gametes? A) pairing of homologous chromosomes B) independent assortment of chromosomes C) trivalent formation D) formation of the meiotic spindle during chromosome segregation E) bivalent formation

B) independent assortment of chromosomes

Assume that you have a garden and some pea plants have solid leaves and others have striped leaves. You conduct a series of crosses [(a) through (e)] and obtain the results given in the table. Define gene symbols and give the possible genotypes of the parents of cross E. (picture chart) A) solid is dominant to striped SS × ss B) solid is dominant to striped Ss × ss C) striped is dominant to solid Ss × ss D) striped is dominant to solid SS × ss E) solid is dominant to striped Ss × Ss

B) solid is dominant to striped Ss × ss

Mendel crossed two pea plants with round seeds. All seeds of the offspring were round. He then crossed a plant with round seeds to a plant with wrinkled seeds and all offspring had wrinkled seeds. Which of the following is true? A) the plants he used were not true breeding B) wrinkled is dominant C) the trait does not breed true D) round is dominant E) a mutation occurred

B) wrinkled is dominant

Tightly curled hair is caused by a dominant autosomal gene in humans. If a heterozygous curly-haired person marries a person with straight hair, what phenotypes (and in what proportions) are expected in the offspring? A) 1 curly : 3 straight B) 2 curly : 1 straight C) 1 curly : 1 straight D) 3 curly : 1 straight E) 1 curly : 2 straight

C) 1 curly : 1 straight

What are two typical testcross ratios? A) 3:1 and 9:3:3:1 B) 3:1 and 1:1:1:1 C) 1:1 and 1:1:1:1 D) 1:1 and 9:3:3:1

C) 1:1 and 1:1:1:1

Which of the following represents the trihybrid ratio if AaBbCc is selfed? A) 18:12:15:9:9:3:3:1 B) 1:1:1:1:1:1:1:1 C) 27:9:9:9:3:3:3:1 D) 9:3:3:1 E) 16:9:9:6:6:3:3:1

C) 27:9:9:9:3:3:3:1

If one is testing a goodness of fit to a 9:3:3:1 ratio, how many degrees of freedom would be associated with the Chi-square analysis? A) 1 B) 2 C) 3 D) 4 E) 5

C) 3

Tightly curled or wooly hair is caused by a dominant gene in humans. If a heterozygous curly-haired person marries a person with straight hair, what percentage of their offspring would be expected to have straight hair? A) 75% curly B) 25% curly C) 50% straight D) 100% straight E) It is impossible to predict the outcome.

C) 50% straight

How many different kinds of gametes can be produced by an individual with the genotype AABbCCddEeFf? A) 16 B) 32 C) 8 D) 64 E) 4

C) 8

How many kinds of gametes will be expected from an individual with the genotype PpCcTTRr? A) 4 B) 1 C) 8 D) 16 E) 2

C) 8

If an F2 generation from a self-cross always yields offspring in a 3:1 phenotypic ratio, which of the following P crosses could have occurred? A) AA × AA B) aa × aa C) AA × aa D) Aa × AA E) aa × Aa

C) AA × aa

A certain type of congenital deafness in humans is caused by a rare autosomal dominant gene. In a mating involving a deaf man and a deaf woman, could all the children have normal hearing? A) No, because it is dominant. Children always get the dominant alleles. B) Yes, because it must be recessive if it's rare. C) Yes, assuming that the parents are heterozygotes (because the gene is rare), it is possible that all of the children could have normal hearing. D) Yes, because traits assort independently. E) No, because children favor their parents.

C) Yes, assuming that the parents are heterozygotes (because the gene is rare), it is possible that all of the children could have normal hearing.

According to Charles Darwin and Alfred Wallace, variations followed a more continuous pattern. According to Mendel's model, variation due to dominance-recessive relationships followed a more ________ form. A) smooth B) abstract C) discontinuous D) transferred E) normalized

C) discontinuous

In studies of human genetics, usually a single individual brings the condition to the attention of a scientist or physician. When pedigrees are developed to illustrate transmission of the trait, what term does one use to refer to this individual? A) mutant B) F1 B C) proband D) child E) cousin

C) proband

The process that leads to development haploid gamete is best described as ________. A) replication B) dominance or recessiveness C) segregation D) Mendelian inheritance E) independent assortment

C) segregation

Assuming independent assortment, what proportion of the offspring of the cross AaBbCcDd × AabbCCdd will have the aabbccdd genotype? A) 1/512 B) 1/256 C) 1/64 D) 0% E ) 1/1024

D) 0%

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene. Two parents with normal pigmentation have an albino child. What is the probability that their next child will be wild type? A) 3/4 B) 1/8 C) 0% D) 3/16 E) 1/2

D) 3/16

Assuming a typical monohybrid cross in which one allele is completely dominant to the other, what ratio is expected if the F1s are crossed? A) 2:1 B) 1:1 C) 3:2 D) 3:1 E) 4:3

D) 3:1

Under what conditions does one expect a 1:1:1:1 ratio? A) AABB × aabb B) Aabb × AABB C) AaBb × AaBb D) AaBb × aabb E) AAbb × aaBB

D) AaBb × aabb

Under what conditions does one expect a 9:3:3:1 ratio? A) dihybrid cross (F1) with independently assorting, completely dominant genes B) dihybrid test cross (F2) with independently assorting, completely dominant genes C) monohybrid test cross (F2) with independently assorting, completely dominant genes D) dihybrid cross (F2) with independently assorting, completely dominant genes E) monohybrid cross (F2) with independently assorting, completely dominant genes

D) dihybrid cross (F2) with independently assorting, completely dominant genes

In a Chi-square test, as the value of the Λ2 increases, the likelihood of rejecting the null hypothesis ________. A) is doubled B) decreases C) increases by a factor of 10 D) increases E) stays the same

D) increases

The Chi-square test involves a statistical comparison between measured (observed) and predicted (expected) values. One generally determines degrees of freedom as ________. A) ten minus the sum of the two categories B) the number of categories being compared C) the sum of the two categories D) one less than the number of classes being compared E) one more than the number of classes being compared

D) one less than the number of classes being compared

Which of the following describes the product law? A) The probability of two or more independent events occurring simultaneously is equal to the sum of their individual probabilities. B) The probably of two linked events occurring simultaneously is equal to the probabilities of each individual event. C) The probabilities of two events occurring in a specific sequence are the product of their individual probabilities squared. D) The probability of two or more independent events occurring simultaneously is equal to the product of their individual probabilities. E) The product of the sum of the probabilities of two simultaneous events describes the ability of those two events to occur together.

D)The probability of two or more independent events occurring simultaneously is equal to the product of their individual probabilities.

The autosomal (not X-linked) gene for brachydactyly, short fingers, is dominant to normal finger length. Assume that a female with brachydactyly in the heterozygous condition is married to a man with normal fingers. What is the probability that their first child will have brachydactyly? A) 2/3 B) 1/4 C) 1/8 D) 3/4 E) 1/2

E) 1/2

Two organisms, AABBCCDDEE and aabbccddee, are mated to produce an F1 that is self-fertilized. If the capital letters represent dominant, independently assorting alleles. What proportion of the F2 genotypes will be recessive for all five loci? A) 1/256 B) 1/1024 C) 1/16 D) 1/64 E) 1/243

E) 1/243

The autosomal (not X-linked) gene for brachydactyly, short fingers, is dominant to normal finger length. Assume that a female with brachydactyly in the heterozygous condition is married to a man with normal fingers. What is the probability that their first child will be a brachydactylous girl? A) 2/3 B) 1/2 C) 1/8 D) 3/4 E) 1/4

E) 1/4

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene (a). Two parents with normal pigmentation have an albino child. What is the probability that their next three children will be albino? A) 3/4 B) 1/4 C) 0% D) 1/8 E) 1/64

E) 1/64

Which types of phenotypic ratios are likely to occur in testcrosses when dealing with two gene pairs for which all the genotypic combinations are of equal viability? A) 2:3, 1:2 B) 12:3:1, 9:7 C) 1:2:1, 3:1 D) 9:3:3:1, 27:9:9:9:3:3:3:1 E) 1:1:1:1

E) 1:1:1:1

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene. Two parents with normal pigmentation have an albino child. What is the probability that their next three children will be wild type? A) 1/4 B) 1/32 C) 3/8 D) 0% E) 3/64

E) 3/64

Assuming complete dominance, a phenotypic ratio of ________ is expected from a monohybrid sib or self-cross. A) 3:2 B) 5:2 C) 1:1 D) 2:1 E) 3:1

E) 3:1

Which of the following best describes the relationship at the molecular level between mutant alleles and phenotype? A) The wild-type allele is always dominant. B) A mutant allele will cause the wild-type protein not to be made. C) A mutant allele will cause only one phenotype. D) Mutant alleles will only cause problems when seen in the homozygous form, no matter the gene affected. E) A mutant allele can have different effects depending on the gene product's function.

E) A mutant allele can have different effects depending on the gene product's function.

For the purposes of this question, assume that being Rh+ is a consequence of D and that Rh^- individuals are dd. The ability to taste phenylthiocarbamide (PTC) is determined by the gene symbolized T (tt are nontasters). A female whose mother was Rh^- has the MN blood group, is Rh+ and a nontaster of PTC, and is married to a man who is MM, Rh^-, and a nontaster. Assume that all the loci discussed in this problem are autosomal and independently assorting. Which of the following is NOT a possible genotype of the children? A) MNddtt B) MNDdtt C) MMddtt D) MMDdtt E) MNDDtt

E) MNDDtt

A certain type of congenital deafness in humans is caused by a rare autosomal recessive gene. In a mating involving a deaf man and a deaf woman, could some of the children have normal hearing? A) No, because the parents would teach their children sign language. B) Yes, because it's rare. C) No, traits get passed down from father to child and the father is deaf. D) Yes, because traits assort independently. E) No, since the gene in question is recessive, both of the parents are homozygous and one would not expect normal hearing in the offspring.

E) No, since the gene in question is recessive, both of the parents are homozygous and one would not expect normal hearing in the offspring.

A cross between two individuals with different phenotypes that resulted in approximately 50% of each type of offspring would indicate the cross was ________. A) a heterozygous dominant crossed to a heterozygous recessive B) true breeding dominant to recessive C) true dominant to a heterozygous dominant D) a homozygous recessive crossed to a heterozygous recessive E) a heterozygous dominant crossed to a homozygous recessive

E) a heterozygous dominant crossed to a homozygous recessive

Mendel indicated that traits were made up of unit factors. Today, we call unit factors ________. A) genotypes B) phenotypes C) genes D) characters E) alleles

E) alleles

What conditions are likely to apply if the progeny from the cross AaBb × AaBb appear in the 9:3:3:1 ratio? A) incomplete segregation and complete dominance B) gene interaction and independent assortment C) dihybrid cross with incomplete dominance D) dihybrid test cross E) complete dominance, independent assortment, and no gene interaction

E) complete dominance, independent assortment, and no gene interaction

According to Mendel's model, because of the ________ of chromosomes during meiosis, all possible combinations of gametes will be formed in equal frequency. A) the product rule B) chromosomal theory of inheritance C) law of segregation D) law of unit factors E) independent assortment

E) independent assortment

In a Chi-square analysis, what general condition causes one to reject (fail to accept) the null hypothesis? A) when observed = expected B) usually when the probability value is less than 0.005 C) when observed >> expected D) usually when the probability value is less than 0.5 E) usually when the probability value is less than 0.05

E) usually when the probability value is less than 0.05