Biologist from University of Houston Published new calculations that indicate the amount of functional human genome is no more than 25%, the rest of all is junk DNA.

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Dan Graur, John and Rebecca Moores Professor of Biology and Biochemistry at University of Houston used simple approach on determining the functional fraction of the genome by using the deleterious mutations rate.

The research entitled "An upper limit on the functional fraction of the human genome" was published online on 11 July 2017.

In the previous studies however, the functional genome in the human was estimated to be much higher (80%). The data is the inference of study conducted by Encyclopedia of DNA Elements (ENCODE) project which had previously systematically mapped regions of transcription, transcription factor association, chromatin structure, and histone modification.

Graur with the help of previous data developed a model to calculate the decrease in reproductive success induced by harmful mutations, known as the “mutational load,” in relation to the portion of the genome that is functional.

He concluded that if 80% of more of the genome was functional, and even if the harmful mutations were at low levels, very high fertility rates would be required to sustain the population .

On Graur's own words- “We need to know the functional fraction of the human genome in order to focus biomedical research on the parts that can be used to prevent and cure disease,” he said. “There is no need to sequence everything under the sun. We need only to sequence the sections we know are functional.”

Source: University of Houston