"United States Census, 1940," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:K7YH-VF2 : accessed 8 May 2018), Opal Setser in household of Grenville Setser, Magisterial District 1, Martin, Kentucky, United States; citing enumeration district (ED) 80-1B, sheet 14A, line 13, family 217, Sixteenth Census of the United States, 1940, NARA digital publication T627. Records of the Bureau of the Census, 1790 - 2007, RG 29. Washington, D.C.: National Archives and Records Administration, 2012, roll 1339.
It may be possible to confirm family relationships with Opal 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 Opal: