Great Migration: Life for Migrants in the City. By the end of 1919, some 1 million blacks had left the South, usually traveling by train, boat or bus; a smaller number had automobiles or even horse-drawn carts.
Genetic variation is increased by meiosis During fertilisation, 1 gamete from each parent combines to form a zygote. Because of recombination and independent assortment in meiosis, each gamete contains a different set of DNA.
It is because the gene coding for the eye color separates independently (and randomly) from the gene coding for the hair color during formation of gametes (meiosis). Independent assortment of genes is important to produce new genetic combinations that increase genetic variations within a population.