e. c. d. a. Use the following list for questions 1-4 a. multiple alleles b. incomplete dominance c. polygenes d. epistatic gene e. pleiotropic gene Individuals with Marfan syndrome tend to be tall, nearsighted, and have a weak aorta. 2. Produces a bell curve of phenotypes. 3. When a recessive pair of alleles at one locus prevents the expression of a dominant allele at another 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 (autosomal recessive). Which could be the genotype of his mother? bbww XbYWw bbXwXw XBXbWw XBXBww Answer: d

What is a genetic cross called between an individual of unknown genotype and a homozygous recessive individual? a self-cross a testcross a hybrid cross an F cross a dihybrid cross Answer: b

A couple has three children, all of whom have brown eyes and blond hair. Both parents are homozygous for brown eyes (BB), but one is blond (rr) and the other is a redhead (Rr). What is the probability that their next child will be a brown-eyed redhead? 1/16 d. 1/2 1/8 e. 1 1/4 Answer: d.

Given the parents AABBCc x aabbCc, assume simple dominance and independent assortment. What proportion of the progeny will be expected to phenotypically resemble the first parent? 1/4 d. 3/8 1/8 e. 1 3/4 Answer: c

Feather color in budgies is determined by two 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, and yybb is white. A green budgie is crossed with a blue budgie. Which of the following results is NOT possible? all green offspring all blue offspring all white offspring all yellow offspring All of the above are possible Answer: e

The inheritance of color in budgies is an example of what genetic phenomenon? pleiotropy penetrance polygenic inheritance dominance epistasis Answer: e

Answer: a In cattle, roan coat color (mixed red and white) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr). When two roan cattle are crossed, the phenotypes of the progeny are found to be in the ratio 1 red: 2 roan: 1 white. Which of the following crosses would produce the highest percentage of roan cattle? red x white roan x roan white x roan red x roan all of the above would give the same percentage of roan cattle. Answer: a

A man who has an x-linked allele will pass it on to all of his daughters half of his daughters all of his sons half of his sons all of his children Answer: a

The following is a map of 4 genes on a chromosome: A 5 W 3 E 12 G Between which two genes would you expect the highest frequency of recombination? A and W d. A and E W and E e. A and G E and G Answer: e.

The phenotypic ratio from a genetic cross is 1:1:1:1. The genotypes of the parents are TTGG x TtGg TtGG x Ttgg TtGg x ttgg Ttgg and ttgg ttgg x ttgg Answer: c

An organism has the genotype DDGg. How many unique kinds of gametes can this organism produce? none one two four eight Answer: c

Two organisms, each with the genotype TtGg mate. The chance of producing an offspring that has the dominant phenotype for height and the recessive phenotype for color is 9/16 7/16 6/16 3/16 1/16 Answer: d

Select the wheat plant genotype with the darkest-colored seeds (the dominant allele of each gene pair contributes an equal amount of red pigment to the seed). AaBbCc AaBBcc AaBbCC AabbCc AAbbCc Answer: c

A culture of white-eyed fruit flies was maintained for many generations. Females from the stock white-eyed culture were crossed with red-eyed (wild type) males. The F1 females were crossed with the white eyed males from the original culture. The resulting phenotypes are listed. P1 cross: white eyed female x red eyed male F1 generation : 100% females red eyed 100% males white eyed F1 cross: red eyed females x white eyed males F2 generation: 50% females red eyed, 50% females white eyed 50 % males red eyed, 50 % males white eyed

The best explanation for the red eyed F1 females is mutation culture contamination dominance multiple loci sex-influenced traits Answer: c

There are white eyed females in the F2 generation because white is a dominant allele. the white allele is autosomal. a mutation has occurred. these F2 females have two white alleles. the white allele is located on the Y chromosome. Answer: d

Which of the following best describes the mode of inheritance of eye color in the white culture. autosomal dominant located on the Y chromosome sex-linked lethal Answer: d

Which represents the genotype of a carrier Female? XAXA XAXa XaXa XAY XaY Answer: b

The shaded individuals are affected with a disorder; the unshaded individuals are not affected. The disorder is most probably x-linked dominant autosomal recessive autosomal dominant epistatic x-linked recessive Answer: c

Which of the following are possible genotypes for persons 7 and 8? Aa x Aa AA x Aa Aa x aa aa x aa AA x AA Answer: c

A type O woman has a type O child. The father could have the blood type A only. B only. A or B A, B, or AB O only. Answer: c

Which genotype could not be produced if both parents have type A blood? type A type O type AB type B both c and d are correct all of the above are correct Answer: e

If the husband is a carrier of Tay Sachs disease (recessive), but the wife is homozygous normal, what are the chances of having a baby with Tay Sachs? 0% 25% 50% 75% 100% Answer: a

Select the syndrome that is trisomy. Turner syndrome Klinefelter syndrome PKU Down syndrome b and d a, b, and d Answer: f

3:1 9:3:3:1 1:1 1:1:1:1 Match the cross with its ratio. TtYy xTtYy Tt xTt Tt x tt TtYy x ttyy b. a. c. d.

A person has a genetic disorder. Which is inconsistent with autosomal recessive inheritance? Both parents have the disorder. Both parents do not have the disorder. All the children (males and females) have the disorder. d. All of these are inconsistent e. All of these are consistent. Answer: e

Cystic fibrosis Huntington’s disease Hemophilia Tay-Sachs disease autosomal dominant most often seen among Jewish people X-linked recessive thick mucus in lungs and pancreatic ducts b. d. c. a.

A male has a genetic disorder. Which of the following is inconsistent with X-linked recessive inheritance? Both parents do not have the disorder. 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.