Galactosemia is a recessive human disease that is treatable by restricting lactose and glucose in the diet. Susan Smithers and her husband are both heterozygous for the galactosemia gene. a. Susan is pregnant with twins. If she has fraternal (nonidentical) twins, what is the probability both of the twins will be girls who have galactosemia? b. If the twins are identical, what is the probability that both will be girls and have galactosemia? For parts c–g, assume that none of the children is a twin. c. If Susan and her husband have four children, what is the probability that none of the four will have galactosemia? d. If the couple has four children, what is the probability that at least one child will have galactosemia? e. If the couple has four children, what is the probability that the first two will have galactosemia and the second two will not? f. If the couple has three children, what is the probability that two of the children will have galactosemia and one will not, regardless of order? g. If the couple has four children with galactosemia, what is the probability that their next child will have galactosemia?

In humans, a dimple in the chin is a dominant characteristic. a. A man who does not have a chin dimple has children with a woman with a chin dimple whose mother lacked the dimple. What proportion of their children would be expected to have a chin dimple? b. A man with a chin dimple and a woman who lacks the dimple produce a child who lacks a dimple. What is the man’s genotype? c. A man with a chin dimple and a nondimpled woman produce eight children, all having the chin dimple. Can you be certain of the man’s genotype? Why or why not? What genotype is more likely, and why?

A man’s grandfather has galactosemia, a rare autosomal recessive disease caused by the inability to process galactose, leading to muscle, nerve, and kidney malfunction. The man married a woman whose sister had galactosemia. The woman is now pregnant with their first child. a. Draw the pedigree as described. b. What is the probability that this child will have galactosemia? c. If the first child does have galactosemia, what is the probability that a second child will have it?

The following chart shows the results of different matings between jimsonweed plants that had either purple or white flowers and spiny or smooth pods. Determine the dominant allele for the two traits and indicate the genotypes of the parents for each of the crosses.

$$\begin{array}{lllll} \text{Parents} & \text{ } & \text{ } & \text{Offspring} & \text{ }\\ \text{ } & \text{Purple} & \text{White} & \text{Purple} & \text{White}\\ \text{ } & \text{Spiny} & \text{Spiny} & \text{Smooth} & \text{Smooth}\\ \hline \text{a. purple spiny $\times$ purple spiny} & \text{94} & \text{32} & \text{28} & \text{11}\\ \text{b. purple spiny $\times$ purple smooth} & \text{40} & \text{0} & \text{38} & \text{0}\\ \text{c. purple spiny $\times$ white spiny} & \text{34} & \text{30} & \text{0} & \text{0}\\ \text{d. purple spiny $\times$ white spiny} & \text{89} & \text{92} & \text{31} & \text{27}\\ \text{e. purple smooth $\times$ purple smooth} & \text{0} & \text{0} & \text{36} & \text{11}\\ \text{f. white spiny $\times$ white spiny} & \text{0} & \text{45} & \text{0} & \text{16}\\ \end{array}$$

Imagine you have just purchased a black stallion of unknown genotype. You mate him to a red mare, and she delivers twin foals, one red and one black. Can you tell from these results how color is inherited,

Among native Americans, two types of earwax (cerumen) are seen, dry and sticky. A geneticist studied the inheritance of this trait by observing the types of offspring produced by different kinds of matings. He observed the following numbers:

$$\begin{matrix} \text{ } & \text{ } & \text{ Offspring} & \text{ }\\ \text{Parents} & \text{Number of mating pairs} & \text{Sticky} & \text{Dry}\\ \hline \text{Sticky $\times$ sticky} & \text{10} & \text{32} & \text{6}\\ \text{Sticky $\times \mathrm{dry}$} & \text{8} & \text{21} & \text{9}\\ \text{Dry $\times \mathrm{dry}$} & \text{12} & \text{0} & \text{42}\\ \end{matrix}$$

a. How is earwax type inherited? b. Why are there no 3:1 or 1:1 ratios in the data shown in the chart?

In Drosophila, males from a true-breeding stock with raspberry-colored eyes were mated to females from a true-breeding stock with sable-colored bodies. In the $\mathrm{F}_{1}$ generation, all the females had wild-type eye and body color, while all the males had wild-type eye color but sable-colored bodies. When $\mathrm{F}_{1}$ males and females were mated, the $\mathrm{F}_{2}$ generation was composed of 216 females with wild-type eyes and bodies, 223 females with wild-type eyes and sable bodies, 191 males with wild-type eyes and sable bodies, 188 males with raspberry eyes and wild-type bodies, 23 males with wild-type eyes and bodies, and 27 males with raspberry eyes and sable bodies. Explain these results by diagramming the crosses, and calculate any relevant map distances.

What is the probability of a child having type AB blood if one of the parents is heterozygous for type A blood and the other is heterozygous for type B? What other genotypes are possible in this child?

Families with 4 children were surveyed. (a) Construct a probability model describing the possible number of girls in the family. (Assume the probability a child is a girl is 0.5.) (b) Find the probability that (i) No children are girls. (ii) Exactly 2 children are girls. (iii)At least one boy and one girl. (iv) At least one child is a boy.

How did the formation of the EC and then the EU change Europe?

How was trade revived in Europe in the 1000s and 1100s?

What groups invaded Europe in the 800's?

How did the Brezhnev Doctrine affect Eastern Europe?

How did the Crusades accelerate change in Europe?