Perhaps the greatest question regarding life comes from its end: what happens when we die? This is a long sought after question, with answers and theories from the different religions, from Buddhism to Christianity. A common undertone to most religions, even Atheism, is the concept of immortality. Scientifically speaking, immortality is a sound and realistic theory—I would go so far as to call it a fact.
What you and I are at the basic genetic level are 46 chromosomes: duplicate copies of the 22 autosomes and 1 sex chromosome—one from the mother and one from the father. Throughout life, each cell in your body replicates these 46 chromosomes during cell division. The majority of cell division is called mitosis, in which a given cell replicates its DNA and splits into two identical “daughter cells”. Through this process, you remain you for your entire life; each of your cells contains identical information (aside from miscellaneous mutations that can be silent or manifest as cancers or other diseases).
Meiosis is the other process of replication, which only occurs in your gametes, or “sex cells” (spermatocytes and oocytes). While the somatic cells in all of your tissues contain 46 chromosomes in total, these gametes contain 23 copies. Upon fertilization of an egg by a sperm cell, 23 of your gamete chromosomes combine with 23 gametes of the opposite gamete type to produce a new form of life with 46 chromosomes.
So which 23 chromosomes are found in your gametes? Are some sex cells comprised of your mother’s DNA and others your father’s? It is an interesting question with an equally interesting answer: the chromosomes of your sperm or egg are actually chimeric combinations of the genes inherited from your parents. Through a process called homologous recombination, certain segments of one chromosome combine with the other during meiosis. In a sense, the genome of your gametes is a more compact version of your entire genome, and each gamete represents a unique combination of your genes; no two gametes are completely identical.
Simply put, your children will be a fusion of your parents and your partner’s parents… this idea gets more complex when you bring in grandparents, great-grandparents, and the most distant ancestors of your lineage.
Whenever I am having discussion with religious/non-religious people, the question of “what exactly are we?” always comes up. I do not pretend to know the ultimate answer to this question; I simply stick to the fact that we are our genome. Everything we are is dictated by segments of A’s, T’s, C’s, and G’s of the genetic code that are unique to each individual person. I am speaking from a physical standpoint of course, i.e. the thickness of your hair, the color of your eyes, etc., because the science regarding consciousness is nowhere near conclusive (although I strongly believe that consciousness/psychological traits are in major part determined by our individual genes).
So how does this all add up to equal immortality? If your gametes are a more-compact-version-of-you and your partner’s gametes are a more compact version of them, your children will essentially be a chimeric 50/50 combination of the two of you, a 25/25/25/25 combination of their grandparents, a 12.5/12.5/12.5/12.5/12.5/12.5/12.5/12.5 combination of their great-grandparents, ad infinitum. Your genes will be in the proverbial ‘gene pool’ until the end of human existence.
Even if you don’t have children, this remains true. Your relatives share many of your genes, and you’re path to immortality is secure in them.
Are the Buddhists correct in that you will be reincarnated in one of your endless future progeny, or do the Christians have it right when they conclude that your spirit will ascend to the heavens and you will be land-locked only by the genes you pass on? Is the Atheistic view accurate in that the only truth is the natural science that dictates life-until-death? We will never know the answers to this question, but what we can take away from the human genome is that we are, as abstract as it may seem, immortal.