Question 1 Suppose a botanist had a group of pea plants, some of which had green

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Question 1

Suppose a botanist had a group of pea plants, some of which had green pods and some of which had yellow pods. It is established that the green pod trait is dominant to yellow pods. The botantist took one of the green pod plants and did a test cross with a yellow pod plant and determined that the green pod plant is heterozygous.   Which of Mendel

Suppose a botanist had a group of pea plants, some of which had green pods and some of which had yellow pods. It is established that the green pod trait is dominant to yellow pods. The botantist took one of the green pod plants and did a test cross with a yellow pod plant and determined that the green pod plant is heterozygous. Which of Mendel?s findings does the test cross illustrate? Select one: law of segregation chromosome theory law of independent assortment blended inheritance Question 2 What allele combinations are possible for gametes generated from an organism with a genotype AAbb? Select one: AA and bb Ab Ab and ab bb Ab, Ab, aB, and ab AA Question 3 A tall, purple-flowered pea plant (TtPp) is allowed to self-pollinate. (The recessive alleles code for short plants and white flowers.) The phenotypic ratio of the resulting offspring is 9:3:3:1. What is the genotype of the plant whose phenotype appeared once out of every 16 offspring (the 1 in the 9:3:3:1 ratio)? Answer: Question 4 A woman homozygous for polydactyly (extra fingers and toes), a dominant trait, is married to a man with 5 fingers and toes. Enter in the textbox below, the probability (between 0 - 1) of this couple producing offspirng that have only 5 fingers and toes. Answer: Question 5 A new species of grasshopper is discovered, varieties are found with red stripes, another with yellow stripes, and a third with orange stripes . Careful genetic analysis shows that the striping pattern observed is controlled by one gene with two alleles. When true-breeding red striped grasshoppers are crossed iwth true-breeding yellow striped grasshoppers, all offspring are orange striped. Question 6 In centaurs, the allele for a long horn, L, is dominant over the allele for a short horn, and the allele for white hair, W, is dominant over brown hair. A long horn, white haired centaur and a short horn, brown haired centaur 15 baby centaurs. All 15 baby centaurs have long horns and white hair. What is the most likely genotype of the long horned, white parent centaur? Answer What is the most likely genotype of the short horned, brown parent centaur? Answer Question 7 A pink unicorn is crossed with a blue unicorn and all of the offspring are lilac, caused by the presence of both pink and blue hair. This is an example of alleles that are _____. Select one: sex-linked codominant completely dominant incomplete dominant epistatic Question 8 In mammals, hair/fur color is determined by the expression of a number of different genes, each of which has two or more alleles. According to Mendel?s second law, unlinked genes (those that are either on different chromosomes or on the same chromosome but very distant from one another) assort independently because they align independently on the spindle during metaphase I of meiosis. In this tutorial, you will solve genetics problems related to the inheritance of fur color in mice. In mice, agouti fur is a dominant trait resulting in individual hairs having a light band of pigment on an otherwise dark hair shaft. A mouse with agouti fur is shown here, along with a mouse with solid color fur, which is the recessive phenotype (A = agouti; a = solid color). A separate gene, which is not linked to the agouti gene, can result in either a dominant black pigment or a recessive brown pigment (B = black; b = brown). A litter of mice from the mating of two agouti black parents includes offspring with the following fur colors: solid color, black solid color, brown (sometimes called chocolate) agouti black agouti brown (sometimes called cinnamon) In addition to A and a, the agouti gene has a third allele, AY . Here is some information about the inheritance of the AY allele. The AY allele is dominant to both A and a. The homozygous genotype (AYAY ) results in lethality before birth. The heterozygous genotypes (AYA or AYa) result in yellow fur color, regardless of which alleles are present for the B/b gene. (This effect exhibited by the AY allele is known as epistasis--when the expression of one gene masks the expression of a second gene.) Suppose you mate two mice with the genotypes AYaBb x AYaBb . Considering only the live-born offspring, what would be the expected frequency of mice with yellow fur? (For help getting started, see Hint below.) Answer must be in numeric form, no words. You may use fractions or decimal numbers. Answer Hint 1. How to approach this problem To calculate the probability that a live-born offspring will have yellow fur, you need to consider this information. The effect of epistasis: Because yellow fur color is epistatic, the genotype of the B/b gene will not affect the fur color of any offspring that inherits an AY allele. For this reason, you can ignore the B/bgene for this problem. The effect of lethality: Because the AYA Y genotype is lethal, zygotes that receive that allele combination will not continue to develop. As a result, when you complete a Punnett square for the first gene of this cross (AYaBbx AYaBb), you need to disregard any ?offspring? with the lethal allele combination. Only consider the remaining offspring in calculating the probability of yellow fur. Question 9 In mice, agouti fur is a dominant trait resulting in individual hairs having a light band of pigment on an otherwise dark hair shaft. A mouse with agouti fur is shown here, along with a mouse with solid color fur, which is the recessive phenotype (A = agouti; a = solid color). A separate gene, which is not linked to the agouti gene, can result in either a dominant black pigment or a recessive brown pigment (B = black; b = brown). A third unlinked gene (gene C/c) also has an epistatic effect on fur color. The presence of the dominant allele C (for color), allows the A/a and B/b genes to be expressed normally. The presence of two recessive alleles (cc), on the other hand, prevents any pigment from being formed, resulting in an albino (white) mouse. Match the phenotypes on the left to the genotypes listed on the right. solid color, black Drag answer here agouti black Drag answer here albino Drag answer here AaBbcc AAbbCc aaBBCC aabbCC AaBBCC

Explanation / Answer

1.A. law of segregation

2. AA and bb

3. ttpp

4. 0.5

5. a. codominance

    b. 9 red : 3 orange : 4 yellow

   c. 1 red : 2 orange : 1 yellow

6. This is a test cross -

    -What is the most likely genotype of the long horned, white parent centaur? -LlWw
    -What is the most likely genotype of the short horned, brown parent centaur? - llww

      LlWw x llww gives LlWw, Llww,llWw, llww (1:1:1:1)

7. completely dominant In incomplete dominance both alleles are expressed in an additive     fashion. Because the offspring are a combination of pink and blue, they show incomplete dominance.

8. a.3/16

b. Out of every 16 total offspring, you would expect four to have the lethal AYAY combination. Of the remaining 12, 8 would receive one copy of the AY allele and be yellow.
Therefore, the probability of live born offspring having yellow is 8/12, or 2/3.

9. Because the C/c gene is epistatic to both the A/a and B/b genes, any offspring with the cc allele combination will be albino. Otherwise, the A/a and B/b genes are expressed normally.
AaBbcc-Albino,
AaBBCC-Agouti Black
Aabbcc-Albono
AAbbCc Agouti Brown
aaBbCc-Solid color, Black
AABBcc-Albino

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