Although there can be individuals born with only a single X chromosome, there are not individuals born who have no X chromosomes. With what you know, why do you think this might be?

What is crossing over and where does it occur in meiosis? Why is crossing over important for creating genetic diversity?

Below is a pair of homologous chromosomes. If the A and B genes are on the same chromosome (as shown), what outcome of gametes would you expect to be produced from this individual? B 16 O 50% AB, 50% ab O More Ab gametes than AB gametes O 25% AB, 25%Ab, 25%aB, 25%ab O More AB gametes than Ab gametes

In fruit flies, chromosomal crossing over does not occur in meiosis in males, whereas crossing over does occur in meiosis in females. In fruit flies that are heterozygous at many genes (i.e. many maternal and paternal versions of the genes differ), at what stage would cells no longer be heterozygous for any gene during the process of meiosis? a)After the second meiotic division in males, and after the first meiotic division in females. b)After the second meiotic division in both males and females. c)After the first meiotic division in both males and females. d)After the first meiotic division in males, and after the second meiotic division in females.

Men are more likely to display an X-linked recessive disorder than are women. Why do you think this is true?

When is the only time crossing over can occur?

What is Nondisjunction? How is it linked to meiosis, mitosis and cancer?

A mother and father have four children; two sons and two daughters. What is the probability that the brothers share the same Y chromosome? 100% 25% 50% 0%