The Gelsenius yDNA Project focuses on identifying and verifying the descendants of Thorerus Caroli (c1580-1654, vicar at Gärdserum, Sweden. He came from Horn. His descendants adopted the surname GELSENIUS, and in later generations GÄRDEMAN, GELSIN and GERDEMAN. Some possible later connections include CAVAT, HYLÉN, ÖGRIM, SVANSTRÖM, and SWANSTROM.
- Family Tree DNA, Gelsenius yDNA Project