ISTOCK, SUPPARSORNUp to 25 percent of the human genome is critical, while the rest has no function, according to a study published July 11 in Genome Biology and Evolution. The estimate, generated by looking at fertility rates and the expected frequency of deleterious mutations, contradicts a 2012 claim from a large international group called ENCODE, which estimated that 80 percent of the genome is functional.
“For 80% of the human genome to be functional, each couple in the world would have to beget on average 15 children and all but two would have to die or fail to reproduce,” writes Dan Graur, an evolutionary biologist at the University of Houston, in his study.
Graur’s model is built on the idea that fertility rates reflect how much of the human genome is vulnerable to deleterious mutations, and therefore functional. If most of the genome is functional, then people would have to have a lot of babies to maintain the human population and make up for the decreased chances of survival that accompany a greater possibility for harmful mutations. If only a small bit of the genome is functional, then the odds ...
