How Can Meiosis Lead To Differences Between Parents And Offspring?
When meiosis occurs, the cells produced (egg or sperm) have only a random sample of half of the DNA of the parent. You have two of each type of chromosome. One from each parent. Those ‘homologous’ chromosome undergo a process called ‘crossing over’ during meiosis, that in essence, reshuffles the genetic deck. Parts of each homologous chromosome detach and trade places with parts the other chromosome. It is these reshuffled chromosomes that will make their way into egg or sperm. So the direct answer to your question is: 1) Crossing over makes the chromosomes in meiotically produced cells unique (not exactly like the parent cell’s chromosomes.) 2) Only one chromosome makes it into a meiotically produced cell, which means that the other chromosome will come from the other parent upon fertilization. Therefore a child is a random sampling of genes from both parents and has different gene combinations than either parent.
