Exam 3: Basic Principles of Heredity

Which of the following crosses would produce a 3:1 ratio of phenotypes in the next generation?

What conclusions did Mendel make from his monohybrid crosses?

An organism produces the gametes shown. Which statement about the meiotic divisions that produced these gametes (assume no crossing over) is TRUE?

What is the difference between a backcross and a testcross?

A cross was made and a chi-square test was done to see if the results were consistent with the expected 1:1:1:1 ratio from this cross. Using p = 0.05 as the cutoff value, which of the following calculated chi-square values would be consistent with the deviations from the expected values being due to chance? (Select all that apply.)

For a particular plant, red flowers (A) are dominant over yellow flowers (a). An initial cross was made between a plant that was correct-breeding for red flowers and another plant true-breeding for yellow flowers. F₁ progeny, all having red flowers, were allowed to self- pollinate and form seeds, which were then planted to generate F₂ progeny. Pollen from all the resulting F₂ plants was pooled and used to fertilize true-breeding yellow plants. What proportion of the progeny resulting from this cross would be expected to have yellow flowers?

Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds. The F₁ progeny are allowed to self-fertilize. -What is the probability of obtaining a round, yellow seed in the F₂?

Two gene loci, A and B, assort independently, and alleles A and B are dominant over alleles a and b. -What is the probability of producing an offspring with the AB phenotype from a cross of AaBb × AaBb?

Compare and contrast Mendel's principle of segregation and the principle of independent assortment.

Freckles are caused by a dominant allele. A man has freckles but one of his parents does not have freckles. What is the man's genotype?

In poodles, black fur is dominant to white fur. A black poodle is crossed with a white poodle. In a litter of four, all of the puppies are black. What is the BEST conclusion?

You have learned that purple flowers are dominant to white in Mendel's peas. When walking the grounds of Mendel's monastery, you come across a stray purple pea plant. You suspect that it is descended from Mendel's experimental plants, but you have no idea of its exact heritage. Propose two ways that you could determine the plant's genotype with respect to the flower color. Assume that you have any other pea plants that you might want to use in your analysis. Provide expected results and interpretations of possible results for your experiments. Which of the two ways would be easier and why?

Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). A true-breeding plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds. What is the genotype of the F₁ progeny?

In dogs, black coat color (B) is dominant over brown (b), and solid coat color (S) is dominant over white spotted coat (s). A cross between a black, solid female and a black, solid male produces only puppies with black, solid coats. This same female was then mated with a brown, spotted male. Half of the offspring from this cross were black and solid, and half of the offspring were black and spotted. What is the genotype of the brown, spotted male?

Why was the pea plant an ideal plant for Mendel to use?

How did Sutton's chromosome theory of inheritance link Mendel's work with a more mechanistic understanding of heredity?

Using the diploid cell shown here (at interphase), illustrate/describe Mendel's principles of segregation and independent assortment.

Round seeds (R) are dominant to wrinkled seeds (r), and yellow seeds (Y) are dominant to green seeds (y). A true-breeding pea plant with round and yellow seeds is crossed to a true-breeding plant with wrinkled and green seeds. -The F₁ progeny are allowed to self-fertilize. What is the probability of obtaining a yellow seed in the F₂?

If both husband and wife are known to be heterozygous for the autosomal recessive condition of albinism, what is the probability that among their four children, three will be normal and one will have albinism?

In deer mice, red eyes (r) are recessive to normal black eyes (R). Two mice with black eyes are crossed. They produce two offspring, one with red eyes and one with black eyes. Give the genotypes of parents and offspring of this cross.