Information about Genetic Genealogy and DNA Testing can be found at:
International Society of Genetic Genealogy
Are George Clayton (1810-1861) and William Clayton (1814-1879)--who wrote the lyrics to the famous LDS hymn "Come, Come, Ye Saints"--cousins? Although this possibility has sometimes been discussed between the descendants of these two well-known Mormon Pioneers such a supposed relationship has never been substantiated. However, if these two men are related and descend from a common ancestral couple then such a relationship would have probably began in the 1500's or earlier.
It is possible that an extensive Y-DNA test--such as a Y-DNA-111 test--might help answer this question. However, it would require that a direct male Clayton descendant of both George Clayton and William Clayton take a Y-DNA test and then compare their DNA markers and matches. Currently the GCFO suggests that such tests be considered, taken and analyzed.
Below is the ancestry of these two well-known Mormon Pioneers.
Edward Clayton, b.abt.1669, of Buxton and Fairfield, Derbyshire, England; died after 1703; had 8 children
Thomas Clayton, b.abt.1690, of Fairfield, Derbyshire, England; died in 1757; married Ann Staley (Stavely) in 1715; had 8 children
Edward Clayton, b.abt.1719, of Fairfield, Derbyshire, England; died in 1795; married Ann White in 1756; had 8 children
Edward Clayton, chr.1758, Fairfield, Derbyshire, England; died in 1836; married Matha Swinscow in 1780; had 12 children
Edward Clayton, chr.1781, Fairfield, Derbyshire, England; died in 1864; married Elizabeth Malkin in 1803; had 9 children
George Clayton, b.1810, Fairfield, Derbyshire, England; died in 1861; married Jane Bingham in 1836; had 3 children
Andrew Clayton, b.abt.1690, of Longton, Lancashire, England; married Mary Shakeshaft in 1712; had at least one child
James Clayton, chr.1728, Penwortham, Lancashire, England; died in 1797; married Jennet Hodson in 1750; had 9 children
Thomas Clayton, chr.1754, Penwortham,, Lancashire, England; died in 1829; married Ellen Mayor; had 7 children
Thomas Clayton, chr.1792, Penwortham, Lancashire, England; died in 1829; married Ann Critchley in 1814; had 14 children
William Clayton, b.1814, Penwortham, Lancashire, England; died in 1879; married Ruth Moon in 1836; had other wives and children