Betts, Mrs. Rebecca, widow of Benjamin Betts, died at Wilton, Conn., aged 100 years, 10 months and 16 days. She left a daughter of 70 and two sons, aged 72 & 74 (Mar. 9, 1805) 
Betts, Frederic H., 1888. Thomas Betts, of Guilford and Norwalk, and his Descendants. (based on the work of Caroli Wyllys Betts, deceased) page 50
↑ American Antiquarian Society, Newspapers and Periodicals (Worcester, Massachusetts. Ancestry.com. (U.S., Newspaper Extractions from the Northeast, 1704-1930 [database on-line]. Provo, UT, USA: Ancestry.com Operations, Inc., 2014. This collection was indexed by Ancestry World Archives Project contributors.)), New York Weekly Museum, 9 March 1805, New York, NY, call number 486670. Cit. Date: 10 Apr 2016.
It may be possible to confirm family relationships with Rebecca by comparing test results with other carriers of her mitochondrial DNA.
However, there are no known mtDNA test-takers in her direct maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Rebecca: