When true-breeding mice with brown fur and short tails (BBtt) were crossed to true- breeding mice with white fur and long tails (bbTT), all F1 offspring had brown fur and long tails. The F1 offspring were crossed to mice with white fur and short tails. What are the possible phenotypes of the F2 offspring? Which F2 offspring are recombinant, and which are parental? What are the ratios of the F2 offspring if independent assortment is taking place? How would the ratios affected by linkage?

1) The possible phenotypes of the F2 offspring are: brown fur, short tails; brown fur, long tails; white fur, short tails; and white fur, long tails.

2) The F2 offspring that are recombinants: brown fur, long tails, and white fur, short tails.

The parental are: brown fur, short tails, and white fur, long tails.

3) The ratio of F2 offspring if independent assortment is taking place will occur in a 1:1:1:1 ratio .

4) if linked, there will be a lower percentage of the recombinant offspring.

americans began to notice growing differences between the northern and southern sections of the country. there were more people living in cities in the north, which made it more urban. more people lived on farms in the south, which made it more rural. while many people were farmers in the northern states, there were now other ways to make a living, such as working in mechanical cotton gins factories manufacturing cloth, tools and other goods. people in the north supported high tariffs on goods imported from europe because the extra cost encouraged people to “buy american” instead. in the southern states, planters did not like tariffs because they sold most of their production to europe and bought their tools from there as well. southerners believed the protective tariff was something that only northern factory owners keep their profits high. so the southern politicians came up with an idea. they would opt out. they would simply ignore the protective tariff. it was ‘null and void’ in south carolina. the state would not collect the taxes on goods imported into south carolina, no matter what the president said they had to do. this decision led to the nullification crisis.