How can genetic recombination though segregation and crossing over during meiosis lead to variation in the offspring?

Question

anonymous · Answer

"Crossing over changes the genes that are on the same chromosome. 

I am going to make an example that should clarify, but it is not a 'real' example as these may not be on the same chromosome... 

If I have the gene for blue eyes and blonde hair on one chromosome, and brown eyes and brown hair on another chromosome (2 different genes), if crossing over happens in between these two genes, I could have a chromosome with blonde hair and brown eyes on one, and brown hair and blue eyes on the other. 

If I was mated to a completely recessive male (blue eyes and blonde hair) normally the only possibilities that my offspring could have would be either blonde with blue eyes or brunette with brown eyes, but now there could be brunette with blue eyes or blonde with brown eyes... 

See the change?" (Yahoo Answers)

anonymous · Answer

yeah, thanks