BIOL 2300 Quiz 2

Mendel crossed peas having round seeds and yellow cotyledons (seed leaves) with peas having wrinkled seeds and green cotyledons. All the F1 plants had round seeds with yellow cotyledons. Based on this cross, what is the probability that an organism in the F2 generation will have round seeds and green cotyledons and be true breeding?

1/16

A husband and wife have normal vision, although both of the couple's fathers are red-green color-blind, an inherited X-linked recessive condition. What is the probability that the couple's first child will be a normal son? Enter your answer as a fraction (example: 3/16) or a whole number (example: 1). Hint: Remember, humans determine sex via the XX = female, XY = male system. Think about the probability of having either a son or a daughter and the probability of having red - green color blindness.

1/4

In foxes, two alleles of a single gene, P and p, may result in lethality (PP), platinum coat (Pp), or silver coat (pp). What ratio is obtained when platinum foxes are interbred?

2/3 platinum::1/3 silver

If you draw one card at random from a deck, what is the probability of drawing any heart? (A deck has 52 cards. Each card has a suit—spade, heart, diamond, or club—and a number [1(Ace)-10] or a face—jack, queen, king. Thus, there are 13 cards of each suit and four cards of each number or face.) Hint: think about whether to use the addition or multiplicative rule.

25%

To assess Mendel's law of segregation using tomatoes, a true-breeding tall variety (SS) is crossed with a true-breeding short variety (ss). The heterozygous F1 tall plants (Ss) were crossed to produce two sets of F2 data, as follows. What is the chi square value for set II? Enter your answer to two decimal places. Can the numbers produced in Set II be attributable to chance? Answer yes or no. Your answer should look like the following: (a number of three significant figures, a semicolon, and either yes or no) Set I Set II 75 tall 750 tall 21 short 210 short

5.00;no

Assume that a dihybrid cross is made in which the two genes are autosomal and independently assorting. Each gene has two alleles which show incomplete dominance. How many different phenotypes would be expected in the offspring? Enter your answer as a number, i.e. if you think the answer is 2 different phenotypes, simply type in 2.

9

In laborador retrievers, pigment color is influenced by two genes. Gene A determines the type of pigment produced and gene B affects whether the pigment gets deposited in the hair shaft. If two heterozygous black laborator retrievers were crossed and offspring were produced in a ratio of 9 black dogs to 3 brown dogs to 4 yellow dogs, what are the genotypes of black dogs?

A_B_

Below is a partial pedigree of hemophilia in the British Royal Family descended from Queen Victoria, who is believed to be the original "carrier" in this pedigree. Analyze the pedigree and indicate which females are also certain to be carriers. Select all answers that apply.

Alice of Hesse, Beatrice, Alice of Athlone

A cross was made between homozygous wild-type female Drosophila and yellow-bodied male Drosophila. All of the resulting offspring were phenotypically wild type. Offspring of the F2 generation had the following phenotypes: Sex Phenotype Number male wild 96 male yellow 99 female wild 197 (a) Is the mutant gene for yellow body behaving as recessive or dominant?[a] (b) is the yellow locus on an autosome or the X-chromosome?[b]

Answers for a: recessive Answers for b: X-chromosome

Two true-breeding pea plants were crossed. One parent is round, terminal, violet, constricted, while the other expresses the respective contrasting phenotypes of wrinkled, axial, white, full. The four pairs of contrasting traits are controlled by four genes, each located on a separate chromosome. In the F1 generation, only round, axial, violet, and full phenotypes were expressed after mating the parents. In the F2 generation, all possible combinations of these traits were expressed in ratios consistent with Mendelian inheritance. Identify the four dominant traits, and enter them in ALPHABETICAL order in the blanks provided. [x],[y],[z],[a].

Answers for: x axial Answers for: y full Answers for: z round Answers for: a violet

In peas, gray seed color (G) is dominant to white (g). For the purposes of this question, assume that Mendel crossed plants with gray seeds with each other and the following progeny were produced: 240 gray and 80 white.

Both parents are Gg

Which of the following was not one of Mendel's conclusions based on his monohybrid crosses?

Genes are carried on chromosomes.

While working in a genetics lab over the summer, you isolated a true-breeding strain of wingless Drosophila. After sharing your results with your mentor, you learn that six other true-breeding strains of Drosophila with the same mutant phenotype have been isolated independently in your lab. Your mentor asks you to determine if the mutants belong to the same complementation group. What is true about flies that belong to the same complementation group? What would be the outcome of crossing two strains of wingless flies that belong to the same complementation group? Select all answers that apply to the two questions.

They all have some mutation in the same wing-development gene. Each strain may have a different mutation, but the same gene is mutated in all strains in a complementation group. and All offspring will be wingless.

Cationic trypsinogen is an enzyme made in the pancreas that helps to digest food. It is encoded for by the PRSS1 gene. Individuals with a disorder called hereditary pancreatitis have mutations in the PRSS1 gene, which result in inflammation of the pancreas, possibly leading to permanent tissue damage. The disorder is inherited in an autosomal dominant fashion.Studies of large human populations have determined that the penetrance of a particular PRSS1 mutation, Arg122His, is 86%. What does this means for individuals with the predisposing genotype?

They have an 86% chance of showing the associated phenotype.

Recessive traits often appear in pedigrees in which there have been consanguine matings, because these traits______________.

appear only when both parents carry a copy of the gene for the trait, the likelihood of which increases if the parents are related.

In a statistical sense, as the sample size increases, the average deviation from the expected fraction or ratio is expected to ________.

decrease

Horses can be cremello (a light cream color), chestnut (a reddish brown color), or palomino (a golden color with white in the horse's tail and mane). Of these phenotypes, only palominos never breed true. The following results have been observed: cremello × palomino → 1/2 cremello 1/2 palomino chestnut × palomino → 1/2 palomino 1/2 chestnut palomino × palomino → 1/2 palomino 1/4 cremello 1/4 chestnut What type of genetic interaction is occurring to determine horse coat color?

incomplete dominance

Albinism in humans is inherited as a simple recessive trait. For the following families, determine the most likely genotypes of the parents. A normal male and an albino female have six children, three normal and three albino. What are the most likely genotypes of the parents?

male Aa; female aa

The fundamental Mendelian process that involves the separation of contrasting genetic elements at the same locus would be called ________.

segregation

Jeff recently purchased a rose bush with pink flowers, a trait known to be caused by a dominant allele. Jeff wants to be sure that this plant is homozygous dominant rather than heterozygous. To do so he should perform a ______ using a known homozygous ______ rose bush with red flowers. The phenotype of the offspring will reveal to Jeff the genotype of the new bush.

testcross, recessive

The genes for zeste eyes and forked bristles are located on the X chromosome in Drosophila melanogaster. Both genes are recessive. A cross is made between a zeste-eyed and normal bristled female and a red eye, forked-bristled male. Assume no crossing over. If the F1 offspring were crossed to produce an F2 generation, what phenotypes would be seen in the offspring? Select all answers that represent an F2 phenotype. Red eyed, normal bristled flies are listed as "wild type" in the answer choices.

wild type females, forked-bristled males, zeste-eyed females, zeste-eyed males