Mendel's laws spring from his work with pea plants in the mid-19th century. His first law, the
Law of Segregation, states that the members of each pair of
alleles separate when
gametes are formed. His second law, the
Law of Independent Assortment, states that two or more pairs of alleles will segregate independently of one another during gamete formation.
Mendel was lucky. All but two of the genes he worked with just happened to be on separate chromosomes, and the two that weren't were on opposite ends of the same chromosome. Thus, independent assortment worked out great for him. Just imagine what would have happened if he'd happened to pick out genes that fell right next to each other on the same chromosome.
Mendel fudged. Yes, it's true. It's been found several times that Mendel fudged his data to make hisnumbers nice and pretty. And you know what? The scientific community didn't seem to care too much. His theories were still pretty sound.