"United States Civil War Soldiers Index, 1861-1865," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:F9R8-YTY : 4 December 2014), George Clise, Private, Company C, 3rd Regiment, Maryland Infantry, Potomac Home Brigade, Union; citing NARA microfilm publication M388 (Washington D.C.: National Archives and Records Administration, n.d.), roll 2; FHL microfilm 881,523.
"Maryland, Civil War Service Records of Union Soldiers, 1861-1865," database, FamilySearch (https://familysearch.org/ark:/61903/1:1:JZK5-7L5 : 4 December 2014), George Clise, 1864; from "Compiled Service Records of Volunteer Union Soldiers Who Served in Organizations from the State of Maryland," database, Fold3.com (http://www.fold3.com : 2010); citing military unit Third Potomac Home Brigade, Infantry, Br-Z, NARA microfilm publication M384 (Washington, D.C.: National Archives and Records Administration, 1963), roll 119.
"United States Census of Union Veterans and Widows of the Civil War, 1890," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:K8SJ-QY2 : 14 November 2014), George Clise, 1890; citing NARA microfilm publication M123 (Washington, D.C.: National Archives and Records Administration, n.d.); FHL microfilm 338,169.
It may be possible to confirm family relationships with George by comparing test results with other carriers of his ancestors' Y-chromosome or mitochondrial DNA.
However, there are no known yDNA or mtDNA test-takers in his direct paternal or maternal line.
It is likely that these autosomal DNA test-takers will share DNA with George: