Use the following list for questions 1-4a. multiple allelesb. incomplete dominancec. polygenesd. epistatic genee. pleiotropic gene

1. Individuals with Marfan syndrome tend to betall, nearsighted, and have a weak aorta.2. Produces a bell curve of phenotypes.3. When a recessive pair of alleles at one locusprevents the expression of a dominant allele atanother locus.4. The ABO blood group system is an example.

e.c.

d. a.

A boy is color blind (sex-linked recessive)and has a continuous hairline (autosomalrecessive). Which could be the genotypeof his mother?

a. bbwwb. XbYWwc. bbXwXw

d. XBXbWwe. XBXBww

Answer: d

What is a genetic cross called between anindividual of unknown genotype and ahomozygous recessive individual?

a. a self-crossb. a testcrossc. a hybrid crossd. an F crosse. a dihybrid cross

Answer: b

A couple has three children, all of whomhave brown eyes and blond hair. Bothparents are homozygous for brown eyes(BB), but one is blond (rr) and the otheris a redhead (Rr). What is the probabilitythat their next child will be a brown-eyedredhead?a. 1/16 d. 1/2b. 1/8 e. 1c. 1/4

Answer: d.

Given the parents AABBCc x aabbCc,assume simple dominance and independent assortment. What proportionof the progeny will be expected tophenotypically resemble the first parent?

a. 1/4 d. 3/8b. 1/8 e. 1c. 3/4

Answer: c

Feather color in budgies is determined bytwo different genes that affect the pigmenta-tion of the outer feather and its core. Y_B_is green, yyB_ is blue, Y_bb is yellow, andyybb is white. A green budgie is crossed with a blue budgie. Which of the following results is NOT possible?a. all green offspringb. all blue offspringc. all white offspringd. all yellow offspringe.All of the above are possible

Answer: e

The inheritance of color in budgies is anexample of what genetic phenomenon?

a. pleiotropyb. penetrancec. polygenic inheritanced. dominancee. epistasis

Answer: e

In cattle, roan coat color (mixed red and white)occurs in the heterozygous (Rr) offspring ofred (RR) and white (rr). When two roan cattle arecrossed, the phenotypes of the progeny arefound to be in the ratio 1 red: 2 roan: 1 white.Which of the following crosses would produce thehighest percentage of roan cattle?a. red x whiteb. roan x roanc. white x roand. red x roane. all of the above would give the same percentageof roan cattle.

Answer: a

A man who has an x-linked allele will passit on to

a. all of his daughtersb. half of his daughtersc. all of his sonsd. half of his sonse. all of his children

Answer: a

The following is a map of 4 genes on achromosome:

A 5 W 3 E 12 G

Between which two genes would youexpect the highest frequency of recombination?a. A and W d. A and Eb. W and E e. A and Gc. E and G Answer: e.

The phenotypic ratio from a genetic crossis 1:1:1:1. The genotypes of the parents are

a. TTGG x TtGgb. TtGG x Ttggc. TtGg x ttggd. Ttgg and ttgge. ttgg x ttgg

Answer: c

An organism has the genotype DDGg.How many unique kinds of gametes canthis organism produce?

a. noneb. onec. twod. foure. eight

Answer: c

Two organisms, each with the genotypeTtGg mate. The chance of producing an offspring that has the dominant phenotypefor height and the recessive phenotypefor color is

a. 9/16b. 7/16c. 6/16d. 3/16e. 1/16

Answer: d

Select the wheat plant genotype with thedarkest-colored seeds (the dominantallele of each gene pair contributes anequal amount of red pigment to the seed).

a. AaBbCcb. AaBBccc. AaBbCCd. AabbCce. AAbbCc

Answer: c

A culture of white-eyed fruit flies was maintainedfor many generations. Females from the stockwhite-eyed culture were crossed with red-eyed(wild type) males. The F1 females were crossedwith the white eyed males from the originalculture. The resulting phenotypes are listed.P1 cross: white eyed female x red eyed maleF1 generation : 100% females red eyed

100% males white eyedF1 cross: red eyed females x white eyed malesF2 generation: 50% females red eyed,

50% females white eyed50 % males red eyed, 50 % males white eyed

The best explanation for the red eyedF1 females is

a. mutationb. culture contaminationc. dominanced. multiple locie. sex-influenced traits

Answer: c

There are white eyed females in theF2 generation because

a. white is a dominant allele.b. the white allele is autosomal.c. a mutation has occurred.d. these F2 females have two white alleles.e. the white allele is located on the Y chromosome.

Answer: d

Which of the following best describes themode of inheritance of eye color in thewhite culture.

a. autosomalb. dominantc. located on the Y chromosomed. sex-linkede. lethal

Answer: d

Which represents the genotype of a carrierFemale?

a. XAXA

b. XAXa

c. XaXa

d. XAYe. XaY

Answer: b

The shaded individuals are affected witha disorder; the unshaded individuals arenot affected. The disorder is most probably

a. x-linked dominantb. autosomal recessivec. autosomal dominantd. epistatice. x-linked recessive

Answer: c

Which of the following are possible genotypes for persons 7 and 8?

a. Aa x Aab. AA x Aac. Aa x aad. aa x aa e. AA x AA

Answer: c

A type O woman has a type O child. Thefather could have the blood type

a. A only.b. B only.c. A or Bd. A, B, or ABe. O only. Answer: c

Which genotype could not be producedif both parents have type A blood?

a. type Ab. type Oc. type ABd. type Be. both c and d are correctf. all of the above are correct

Answer: e

If the husband is a carrier of Tay Sachsdisease (recessive), but the wife is homozygous normal, what are the chances of having a baby with Tay Sachs?

a. 0%b. 25%c. 50%d. 75%e. 100%

Answer: a

Select the syndrome that is trisomy.

a. Turner syndromeb. Klinefelter syndromec. PKUd. Down syndromee. b and df. a, b, and d

Answer: f

a. 3:1b. 9:3:3:1c. 1:1d. 1:1:1:1

Match the cross with its ratio.1.TtYy xTtYy2. Tt xTt3. Tt x tt4. TtYy x ttyy

b.a.

c. d.

A person has a genetic disorder. Whichis inconsistent with autosomal recessiveinheritance?

a. Both parents have the disorder.b. Both parents do not have the disorder.c. All the children (males and females) have the disorder.d. All of these are inconsistente. All of these are consistent.

Answer: e

a. Cystic fibrosisb. Huntington’s diseasec. Hemophiliad. Tay-Sachs disease

1. autosomal dominant2. most often seen among Jewish people3. X-linked recessive4. thick mucus in lungs and pancreatic ducts

b. d.

c.

a.

A male has a genetic disorder. Which ofthe following is inconsistent with X-linkedrecessive inheritance?

a. Both parents do not have the disorder.b. Only males in a pedigree chart have the disorder.c. Only females in previous generations have the disorder.d. Both a and c are inconsistent.

Answer: c.

B represents a dominant allele and b represents a recessive allele. If in 1,000 offspring 75% express the dominant trait, which of the following are most probably the genotypes of the two parents?a. Bb and Bb

b. Bb and bb

c. BB and bb

d. BB and Bb Answer: a

In dogs, the trait for a dark coat (D) is dominantto an albino coat (d) and the trait for short hair (S) is dominant to long hair (s). In a particular cross of dogs, the probability of the offspring having a dark coat is 1/2 and the probability of having short hair is ¾. Which of the following most probably represents the parental genotypes?a. DdSs and ddSs

b. DdSs and DdSs

c. DdSs and ddss

d. DDSs and ddSs Answer: a

In dogs, eye color is controlled by a single gene with two alleles. When a homozygous brown eyed dog is crossed with a homozygous blue eyed dog, green eyed offspring are produced. If the green eyed dogs are mated with each other, what percent of their offspring will have green eyes?

a. 0%

b. 25%

c. 50%

d. 75%

A child has blood type B. The mother has blood type A. The father must have which blood type(s)?

a. AB only

b. Either AB or B

c. Either AB or O

d. Either AB or A

In humans, color blindness is an x-linked recessive characteristic. If a color blind woman has offspring with a normal sighted male, what percentage of their boys will be color blind?a. 25%

b. 50%

c. 75%

d. 100%