Infant development experts say that teething usually starts when your baby is around four months old, and continues until he or she is about two years old, at which time you get a reprieve until about five years old when the baby teeth start being replaced by grown-up teeth.
Quick Answer. Meiosis contributes to genetic variation by creating new groups of genes, according to the University of Miami Miller School of Medicine. The new groups are created when chromosomes passed down from a mother and father share instructions encoded into genes.
Random assortment of chromosomes produces many variations among daughter cells, giving rise to genetic diversity in offspring. A cell with 2 pairs of chromosomes gives 4 possible chromosome combinations in daughter cells (2^2).here are three mechanisms responsible for this: random assortment of chromosomes (chromosomes are sorted into daughter cells randomly), crossing over (chromosomes switch chunks of DNA) and random fertilization (chance alone is responsible for which sperm meets which egg).