Mendel’s principle of independent assortment says that the genes controlling different traits are inherited independently of one another. Today, we know that is ONLY true when

Question

a mutation causes abnormal cell division.

the traits are both recessive.

the traits are located on the same chromosome.

the traits are located on different chromosomes.

the trait occurs on the X or Y chromosome.

Answer 1

The answer should be "the traits are located on different chromosomes". The major exception to the Mendel's Law of Independent Assortment are linked genes, which are on the same chromosome and will not assort independently. That does not mean he's never right in the modern age, just that a lot of modern genetics includes non-Mendelian inheritance!

Answer 2

Answer D is correct: When the genes controlling different traits are located on different chromosomes, they assort independently of each other during meiosis. Which chromosome 1 will you pass on to your egg (if you are a woman) or sperm (if you are a man) — the one you inherited from your dad or the one you inherited from your mom? Which chromosome 2 ... etc., same question. The answer for each chromosome is random and does not depend on what happens with the other chromosomes. “Does not depend” means “independent” in the phrase “independent assortment.”

Here is a general tip when answering multiple choice questions: When two of the choices are very similar, probably the correct answer is one these two. In this case, you can narrow your choices to: “The traits are located on the same or different chromosomes,” and ignore the other choices.