I’m certainly no DNA expert.
But here’s some thoughts anyway. First of all, finding any sort of Hebrew DNA anywhere in the Americas certainly gives critics of the Book of Mormon pause, as it directly refutes some of their arguments. But how important is this discovery?
Let’s talk about the name Cohen first. As I learned from Quest for the Lost Tribes, the name Cohen represents the Tribe of Levi. This is the priesthood tribe. As we go back to the 12 Tribes of Israel, remember that the Tribe of Levi was given no land of inheritance, but was instead granted the priesthood to administer among the other tribes.
Simcha Jacobovichi claims to have found a group of Cohens in Northern Africa, and as the Mormon Times article states, the Lemba Tribe in Southern Africa may be related to this Cohen DNA. (For more info on the Lemba tribe in Africa, you can download an episode of Digging for the Truth for just $2. It is a truly fascinating episode. It took me about an hour to download it on DSL. I liked the episode so much, I purchased seasons 1 and 2 on DVD.)
Anyway, the point is that Lehi was from the Tribe of Manasseh, not Levi. So, while the DNA is Hebrew, it is from the wrong tribe as far as the Book of Mormon is concerned. Will the correct tribe be found someday? Time will tell. If they can find Levi, perhaps they will find Mannaseh at a later date……