GENETICS EXAM!!!!!

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 x aa B) AA x aa C) Aa x AA D) aa x Aa E) AA x AA

B) AA x aa

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

B) 1:1 and 1:1:1:1

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: 1 straight B) 1 curly: 3 straight C) 1 curly: 2 straight D) 3 curly : 1 straight E) 2 curly: 1 straight

A) 1 curly: 1 straight

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) 1/2 B) 1/4 C) 2/3 D) 3/4 E) 1/8

A) 1/2

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

A) 1:1:1:1

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

A) 9:3:3:1

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) crossing the plant to one you know has the recessive trait B) Crossing the plant to a plant of the same type of any color C) Crossing the new plant to one you know has the dominant trait D) selfing the plant E) sequencing the DNA for the trait

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

Mendel law of segregation is supposed by a _____________ test cross ratio A) 2:1 B) 1:1 C) 3:1 D) 5:2 E) 3:2

B) 1:1

What is independent assortment A) chromosomes can swap information during meiosis B) during gamete formation, segregating pairs of unit factors assort independently of each other C) fertilization is random D) genes lie on chromosomes E) 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

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) 3/4 B) 7/16 C) 1/2 D) 1/32 E) 1/8

C) 1/2

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) 25% curly B) 100% straight C) 50% straight D) 75% curly E) It is impossible to predict the outcome

C) 50% straight

what is segregation A) genes lie on chromosomes B) fertilization is random C) during gamete formation, allele pairs are separated to form haploid gametes D) during gamete formation, segregating pairs of unit factors assort independently of each other E) chromosomes can swap information during meiosis

C) during gamete formation, allele pairs are separated to form haploid gametes

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) Thomas Hunt Morgan; Drosophila B) Boris Ephrussi; Ephestia C) gregor Mendel; visum sativum D) Calvin Bridges; Drosophila E) George Beadle; neurospora

C) gregor Mendel; visum sativum

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

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 Masses a woman with normal teeth. What is the probability that their first child will have dentinogenesis imperfecta? A) 1/4 B) 3/4 C) 1/8 D) 1/2 E) 100%

D) 1/2

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) 50% B) about 90% C) 25% D) 75% E) about 66%

D) 75%

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

D) 9:3:3:1

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

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 some of the children have normal hearing? A) No, because the parents would teach their children sign language B) yes, because its rare C) No, traits get passed down from father to child and the father is deaf D) 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) Yes, because traits assort independently

D) 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) true breeding dominant to recessive B) a homozygous recessive crossed to a heterozygous recessive C) true dominant to a heterozygous dominant D) a heterozygous dominant crossed to a homozygous recessive E) a heterozygous dominant crossed to a heterozygous recessive

D) a heterozygous dominant crossed to a homozygous recessive

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

D) a minimum of two contrasting forms of a gene

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 = recessive B) albino= dominant; black recessive C) albino = dominant; black = incompletely dominant D) albino = recessive ; black = dominant E) albino and black = codominant

D) albino = recessive ; black = dominant

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 wrinkles seeds. Which of the following is true? A) a mutation occurs B) the trait does not breed true C) round is dominant D) wrinkled is dominant E) the plants he used were not true breeding

D) wrinkled is dominant

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 children factor their parents B) No, because it is dominant. Children always get the dominant alleles C) Yes, because traits assort independently D) Yes, because it must be recessive if its rare E) Yes, assuming that the parents are heterozygous (because the gene is rare), it is possible that all of the children could have normal hearing.

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

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