Oh, for pity's sake. The DNA didn't "strongly suggest" anything of the sort, and it would be nice if someone who's going to write an entire book on the subject could have been bothered to read the DNA report itself, rather than the summaries provided in the "news" media, which drew conclusions not in evidence.
In truth, the DNA tests could only be done on the descendant lines of two of Hemings' children, her oldest son, Tom, and her youngest, Eston. They showed conclusively that NO Jefferson male fathered Tom, which is rather interesting insofar as the original rumors about Jefferson and Hemings, circulated during his lifetime by disgruntled political opponents, centered around this child. While the DNA tests allowed for the possibility that one of the 25 adult Jefferson males living when Hemings conceived Eston could have been the father, it is scientifically impossible to narrow it down any further, not to a definite relationship and certainly not to a definite on a specific father.
I always found it interesting that every news outlet on the planet trumpeted the claim that Thomas Jefferson had been "proven" to have fathered all of Hemings' children - a flat-out lie - almost none of them bothered to print the correction that followed, and certainly not prominently.