Alleles in heterozygote do not blend, segregate during gamete formation. Each gamete has equal chance of possessing either allele of a pair. Chromosomes segregate in meiosis, like Mendel's alleles. Gametes haploid, one of each allele. Chromosomes assort independently during meiosis.
More genes assort independently than there are chromosomes.
First demonstration by Curt Stern. Chromosomes show evidence of physical exchange. Genetic Maps 1. Crossing over occurs more frequently as the distance between two genes increases. Genetic map shows relative position of genes.