Darwin in the Genome

Guest blog by Lynn Helena Caporale
Author of Darwin In the Genome: Molecular Strategies in Biological Evolution
Watch her interview on The Woman's Connection YouTube Vlog

We are fortunate to be living at this very moment in human history, when we have the power to uncover the information passed from generation to generation, encoded in our genomes and those of all that is alive.  As chemists, biochemists, engineers and computer scientists and mathematicians develop even faster, automated methods for analyzing DNA, it all may seem so technical and aloof from the concerns of most people, and yet this work not only will transform medical research, but also will has profound implications for human society.  

As we look within our own genomes, what we find resonates with the teachings of many great religions, that we are all profoundly connected to each other, and to all life on earth.  The information carried within the genome of any one of us, the order in which the 4 different chemical letters that make up our DNA are arranged as beads on an approximately 3 billion letters string, is 99.97% the same as that of a perfect stranger.  While we may have been raised in very different environments, from a multi-million population urban center to a rural setting in an unindustrialized nation, raised to follow one religion or another, we all are, profoundly, at our core, so similar to each other.  

Each of us has inherited our very similar DNA from 2 parents, 4 grandparents, 8 great-grandparents. If we go back several hundred years, we will find that we, and others we never met, perhaps you and I, share many ancestors in common.  Our close relationship with all people extends into the future, as descendants of ourselves and members of our families meet and marry descendants of others alive today and share in the creation of new generations of children, and should extend to our hopes to build together the kind of future in which our shared children can thrive.  

Some of the strands in the very DNA molecules within our bodies have come to us across countless generations, as the two strands of the DNA double helix separate and are copied, to be passed on as two half-new double helices every time a cell divides. If we could step back in time to retrace our DNA¹s path, we will come to some very unexpected ancestors. We and chimps share a common ancestors, as do, towards the end of the large dinosaur era, we, chimps and mice.  Even further back, we all share ancestors with plants, and much much further back in time with bread yeast and even bacteria.  All life on earth [except some viruses] uses DNA as its genetic material, and must copy this same DNA using highly similar molecular machinery.  All life runs its metabolism with similar chemistry.  There are so many molecular similarities within all life on earth because we are all descended from the same life forms that evolved these capabilities and passed the information on to its progeny encoded in DNA.  As different families of living things emerged, they built upon a common framework.  Whether a fertilized egg is from a hummingbird egg or a frog or a human, it must carry information to make two eyes connected to a brain, four limbs, to digest food, dispose of waste, and to have a heart beating inside.

It is hard to conceive of how the journey of evolution could have taken place.  Of course, it also is hard to imagine how a single fertilized egg can, within nine months, develop into a baby with two eyes, four limbs, eyelashes, and curiosity about the world. We may find it hard to conceive of evolution, but then we realize that it is hard to conceive of such long periods of time.  In my book Darwin in the Genome, I propose that just as we learn about the world by living in it, life learns about adapting to new environments by surviving.  Life becomes better at evolution by survival from generation to generation.  While discussions about Darwin often emphasize ³survival of the fittest,² calling up images of fierce competitive fighters, in Darwin in the Genome I emphasize the importance of diversity and cooperation for survival.  Even bacteria cooperate, using a framework that enables them to share information about antibiotic resistance.   Diversity also is an essential part of fitness.  If we were not diverse, we might all have been wiped out as new pathogens spread rapidly through ancient communities.  As night owls guard the campfire at night, early risers came to relieve them in the pre-dawn hours.  As we look within our genomes, and those of other living creatures, I expect that we will come to treasure the diversity of the human species, and indeed, come to treasure the diversity of all life on earth.