As I wrote in an earlier post, my research into the Gibson family, even from the beginning, has directed me into areas that discuss blurred racial lines. Some of the first material I found that mentioned the Gibson family of South Carolina was contained in a PBS Frontline special that profiled "blurred racial lines of famous families."
The Gibson family was included in this PBS Frontline material, because a number of genealogists have attempted to trace the ancestry of two recent U. S. presidents to the South Carolina Gibson family. Another source of information, included in the Frontline special background materials, was a reference to Winthrop Jordan's book, "White Over Black." In this book, a published doctoral thesis, Jordan mentions Jacob and Joseph Gibson, who are identified as a son and a grandson, respectively, of Randal Gibson. According to Jordan's book, as well as other sources of information I have reviewed and written about, Randal Gibson was a descendant of the South Carolina Gibson family, a family of colour that migrated from South Carolina to Mississippi, Kentucky, and Louisiana.
Another source of material that discusses the likely ethnicity of the Gibson family is the work of Paul Heinegg, Free African Americans of Virginia, North Carolina, South Carolina, Maryland, and Delaware." This work lists surnames by area or location, and can be found at http://www.freeafricanamericansofcolor.com/.
According to Heinegg's book, which was also mentioned in the PBS Frontline special, the Gibson family likely descended from Gibson Gibson, born in the mid-1600's to Elizabeth Chavis. Gibson and Chavis are both surnames that can be found among "core surnames" of a controversial and widely-researched "tri-racial isolate" group, known as Melungeons, that lived in the Southeastern portion of the United States. More can be read about the this group at http://www.melungeons.com.
In June 1977, Erique Eugene Gildemeister drafted the results of his research about the racially mixed people of South Carolina, entitled “Local Complexities of Race in the Rural South: Racially Mixed People in South Carolina.” (B. A. thesis, Board of Study in Anthropology, State University of New York, College at Purchase, Purchase, New York, 1977.) Gildemeister's thesis discusses the various groups of people who lived in South Carolina, including those who were of African and Indian descent.
One conclusion drawn by Gildemeister seems to be that blurring of racial lines between whites and other people who have varying degrees of darker skin, or "mixed-blood", regardless of the specific type of ethnic ancestry, may have enabled the latter over time to be accepted as "white."
Still, I have no pictures of any relative who bore the surname Gibson, so I don't know that I will ever know the true ethnicity of my Gibson ancestors. But at this point, the case for their mixed-racial heritage seems to be a fairly strong one.