Natural selection is the axiom of evolutionary biology. Humans, however, can manipulate natural selection in ways that sometimes contradict it.

Natural selection is the axiom of evolutionary biology.  Humans, however, can manipulate natural selection in ways that sometimes contradict it.  One example is consanguineous mating, a practice that is both common and ancient in Saudi Arabia despite its clearly negative effect on reproductive fitness.  The perceived societal benefits of consanguineous marriages are not sufficient to compensate for the reduced reproductive fitness and there must be compensatory biological factors perhaps the most significant of which is high fertility (a common co-variable).  This long term “tug of war” has left many imprints on the Saudi genome with important medical implications.  These include the conspicuous lack of the “purging effect” and the consequences of that on carrier frequency interpretation and overall Mendelian disease burden in the society.  Furthermore, the characteristic signature of autozygosity presents numerous opportunities for the annotation of the human genome.  In my talk, I will discuss these points in detail based on our experience with large scale medical genomics in Saudi Arabia.