Ever wonder how your sister got the beautiful blond hair and you got stuck with a mousy brown colour? Or why your brother is 3 inches taller than you are? It is all the fault of Meiosis. Check out this video to see the big “why” as to who got what parts and pieces of the parents. Meiosis is the key. How humans, or anything, grow into the organisms they are today hinges on this process. Much of why we are not all just single-celled blobs is still unexplained, but the beginning of what we do know starts right here with this clip. See how the little bits of us on the microscopic level actually know what they are doing to create more of, well, us. The parts we love and the parts we don’t love so much are shown in this short clip. The pieces that make up DNA are merged together, multiplied and then split apart so it can happen all over again, and again, and again, and again…to get us to what we are today.
The cell prepares for meiosis just as it does for mitosis. But as the DNA condenses finds its homologous counterpart. These matching pairs of chromosomes hold equivalent genetic information, one set form mother and one set from the father. Next comes the first shuffle of nature’s genetic deck. The two homologous trait genes in the process called crossing over. This forms new hybrid chromosomes. The spindle then places maternal and paternal chromosomes randomly on each side of the midline. It is another shuffle that can lead to a host of different genetic outcomes. Finally, spindle fibres pull the homologous apart. This leaves the sister chromatid intact. With twice the amount of genetic information, the cells will need, nature must cut the genetic deck in two. The second division produces four unique sets of chromosomes. Because they carry half the genetic information, we call these haploid cells. Many of them will mature into sperm and eggs. The reproductive cells are called gametes.