It appears that the family tradition created in the 1990s by family historians that William Todd d 1820 Horry County South Carolina was the William Todd born Dec 1745 in MOffatt, Dumfriesshire is incorrect. It appears that this was a guess based on assuming that this William Todd of Horry County was from Scotland, that his father was Thomas, and then finding a William Todd son of Thomas in Moffatt parish registers.
DNA reveals that the male DNA of the Horry County Todds match the family of John Todd b 1734 Scarborough, Yorkshire. This family is close genetically to the family of Christopher Todd 1616-1686 who came to New Haven CT in 1639 from Yorkshire. All the DNA evidence points to an English origin, not a Scottish one.
Also, male DNA from a Tod family of Moffat does not match the DNA of the Horry County Todds.
Also, the male DNA of Richard Todd d 1809 Horry County matches the DNA of William Todd d 1820 Horry County. So they are close kin.
see my website at toddmcmurtrieportal.com for more details or send me a personal message.
Richard McMurtry