Question 1

A strain of a cereal grain can be either dark tan, medium-dark tan, medium tan, light tan, or cream colored. When a dark tan and a cream plant are crossed, all F₁ are medium tan. The F₂ are distributed in a ratio of 1:4:6:4:1 from darkest to lightest. How many genes are involved in this coloration?

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Question 2

After locating a genome region likely to include a QTL, what must be found in this region?

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Question 3

If a trait results from genetic variation as well as environmental factors, it is known as a ________ trait.

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Question 4

What is the statistically acceptable lod score that provides evidence of genetic linkage?

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Question 5

Which component of variance in a trait such as stamina in horses is the best indicator of whether the trait will respond to selection?

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Question 6

Which will exhibit the most shared maternal effects (uterine environment, etc.), identical or fraternal twins?

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Question 7

If the odds ratio for a particular QTL/DNA marker pair (e.g., Q₁₀M₁₀)is 2.2, this indicates that the organism is how many times more likely to get Q₁₀M₁₀ gametes?

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Question 8

In some traits, different phenotypes result from genes whose alleles each contribute a specific increment to the whole. The phenotypes then have a ________ phenotypic distribution.

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Question 9

If H2 for club foot is estimated as 80%, would you expect a small difference in concordances between MZ and DZ twins, such as 30 versus 27, or a large difference, such as 30 versus 2?

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Question 10

Of mean, median, and modal, what value is the most common value in a given population?

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Question 11

For the following traits, the concordances (occurrence of the same phenotype)of MZ and DZ twins are given as percentages. Which trait shows the most genetic as opposed to environmental influence?

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Question 12

If we suppose that a specific QTL is genetically linked to a DNA marker at a recombination frequency of 10%, then the parental type combinations in gametes would be expected at what frequency?

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Question 13

A polygenic trait is influenced by the effect of several genes. Although one or more of these may be major genes, many others with lesser effects are known as what type of gene?

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Question 14

What two measures describe the distribution of a trait in a sample?

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Question 15

Calculate the narrow sense heritability (h₂)for the following data on a trait in turkeys: V_A = 11.0 V_E = 94.4 V_P = 114.2 V_D = 13.8

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Question 16

If a trait results from the action of several genes, it is called a ________ trait.

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Question 17

For a specific desirable trait in a breed of sheep, V_P is 28.6, V_C is 11, and V_A is 7.2. What is its broad sense heritability?

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Question 18

A homozygous plant has sepals of 30-cm flowers while another homozygote of the same species has 40-cm flowers. The F1 flowers are all 35 cm. In the F₂, out of 600 plants the smallest flowers were 30 cm and the largest were 40cm; all the others were of intermediate sizes. If all the genes involved in flower size are additive, how many gene pairs are there?

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Question 19

Of the variance and the standard deviation for a set of data about a trait, which represents the square of the difference between each of the values and the mean of the sample, divided by the degrees of freedom?

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Question 20

A strain of a cereal grain can be either dark tan, medium-dark tan, medium tan, light tan, or cream colored. When a dark tan and a cream plant are crossed, all F₁ are medium tan. The F₂ are distributed in a ratio of 1:4:6:4:1 from darkest to lightest. How many additive alleles are needed to produce the darkest phenotypes?

Accepted Answer